Master Vocabulary Reference

Languages: தமிழ் (Tamil) · हिन्दी (Hindi) · Français · 한국어 (Korean) · 日本語 (Japanese).

Keep this document open while you read course material. Look up unfamiliar terms in your first language; learn the English terms over time. The visual cues and sentence frames help you USE each term, not just translate it.

How to use this reference

Each term has the same five elements:

• English term: the heading.
• Definition: a student-friendly explanation in plain English.
• Visual cue: a suggested image or diagram to help you picture the concept.
• In a sentence: an example sentence showing how to USE the term in context.
• 5-language translations: starting reference in Tamil, Hindi, French, Korean, Japanese.

Organization: Terms are grouped by unit (U0 through U7), in roughly the order they appear in the unit. Length: ~140 terms total. Don't try to memorize everything: use the reference as a working dictionary. Search: Use Cmd+F (Mac) / Ctrl+F (Windows) to find a specific term.

Jump to a unit: U0 · U1 · U2 · U3 · U4 · U5 · U6 · U7

Unit 0: Scientific Practices & Class Foundations (15 terms)

OPVL

Definition: A framework for evaluating sources: Origin, Purpose, Value, Limitations. The four questions you ask of any source before trusting it.

Visual cue: Four-quadrant diagram showing O / P / V / L as the four corners of a square.

In a sentence: "Before citing this article, I'll apply OPVL, first its Origin, then its Purpose, then what it's good for, then what it can't tell me."

Tamil	Hindi	Français	Korean	Japanese
மூலம், நோக்கம், மதிப்பு, வரம்புகள் (loanword OPVL commonly used)	मूल, उद्देश्य, मूल्य, सीमाएँ (loanword OPVL commonly used)	Origine, But, Valeur, Limites (anglicisme OPVL souvent utilisé)	출처, 목적, 가치, 한계 (영어 OPVL 그대로 사용 가능)	出典・目的・価値・限界（OPVLという略語をそのまま使うことが多い）

Source

Definition: Any piece of information you cite or learn from, a book, article, website, person, AI output, image, dataset.

Visual cue: A document with an arrow pointing to a student reading it.

In a sentence: "My main source for this claim is a peer-reviewed paper from 2023."

Tamil	Hindi	Français	Korean	Japanese
ஆதாரம் / மூலம்	स्रोत	source	출처 / 자료	出典・情報源

Primary source

Definition: A first-hand source, the original document, original research, or direct testimony, not a summary or interpretation by someone else.

Visual cue: A 1923 newspaper photograph vs. a 2025 article that quotes from it.

In a sentence: "For the 2015 floods, the IMD rainfall data is a primary source; the Wikipedia article is a secondary source."

Tamil	Hindi	Français	Korean	Japanese
முதன்மை ஆதாரம்	प्राथमिक स्रोत	source primaire	1차 자료 (primary source)	一次資料

Secondary source

Definition: A source that summarizes, analyzes, or interprets primary sources. Useful for context but should be cross-checked.

Visual cue: A textbook chapter that cites many original research papers.

In a sentence: "I started with a secondary source to understand the topic, then went to primary sources for the specific numbers."

Tamil	Hindi	Français	Korean	Japanese
இரண்டாம் நிலை ஆதாரம்	द्वितीयक स्रोत	source secondaire	2차 자료 (secondary source)	二次資料

Evidence

Definition: Information that supports a claim. Strong evidence is specific, well-sourced, and relevant to the exact claim.

Visual cue: An arrow from data → claim. "This data supports this claim."

In a sentence: "The evidence for human-caused climate change comes from temperature records, ice cores, and atmospheric CO₂ measurements."

Tamil	Hindi	Français	Korean	Japanese
ஆதாரம்	साक्ष्य	preuve / élément de preuve	증거	証拠

Argument

Definition: A claim plus the reasoning and evidence that supports it. An argument is more than an opinion: it gives reasons.

Visual cue: A claim with multiple lines connecting it to supporting evidence.

In a sentence: "Her argument is that the Cooum should be restored because it would reduce flooding, and she supports this with engineering studies."

Tamil	Hindi	Français	Korean	Japanese
வாதம் / விளக்கம்	तर्क	argument	주장 / 논증	主張・議論

Hypothesis

Definition: A testable prediction about what will happen, based on prior knowledge. Different from a guess: must be possible to prove wrong.

Visual cue: An "if … then …" sentence with a question mark over it.

In a sentence: "My hypothesis is that if rooftop solar is mandated, Chennai's grid stress in summer will decrease."

Tamil	Hindi	Français	Korean	Japanese
முதலியக்கருத்து / கருதுகோள்	परिकल्पना	hypothèse	가설	仮説

Observation

Definition: Something you directly see, measure, or detect. Different from interpretation (what you think it means).

Visual cue: Eye looking at a phenomenon, with a note: "what I see" not "what I think it means."

In a sentence: "My observation: the river is darker now than in 2010 satellite images. My interpretation: this suggests increased pollution."

Tamil	Hindi	Français	Korean	Japanese
கண்காணிப்பு	अवलोकन	observation	관찰	観察

Inference

Definition: A conclusion you draw based on observation + reasoning. Inferences can be strong (well-supported) or weak (jumping to conclusions).

Visual cue: Observation → arrow → conclusion (with a question mark over the arrow asking "is this jump justified?").

In a sentence: "From the riverbed evidence, scientists infer that Mars once had liquid water."

Tamil	Hindi	Français	Korean	Japanese
ஊகம் / அனுமானம்	अनुमान	inférence	추론	推論

Bias

Definition: A systematic preference for or against something that affects how a source presents information. All sources have some bias; the question is which kind and how much.

Visual cue: A scale tipped toward one side, labeled with the source's likely interest.

In a sentence: "The coal industry's report has a bias toward downplaying air-quality impacts."

Tamil	Hindi	Français	Korean	Japanese
சார்பு / பாரபட்சம்	पूर्वाग्रह / पक्षपात	biais	편향	バイアス・偏り

Citation

Definition: A reference to where information came from. Includes author, date, title, and where to find the source.

Visual cue: A footnote symbol attached to a sentence.

In a sentence: "Every claim in my Source Dossier needs a citation showing where the evidence came from."

Tamil	Hindi	Français	Korean	Japanese
மேற்கோள் / குறிப்பு	उद्धरण / सन्दर्भ	citation / référence	인용 / 참고문헌	引用・参考文献

Hallucination (AI)

Definition: When an AI confidently invents information that isn't true, like a citation, a statistic, or a date. AI doesn't know it's hallucinating.

Visual cue: An AI speech bubble with sparkles and a question mark, looks real but is fake.

In a sentence: "The AI told me a specific 1923 quote that doesn't exist anywhere, a hallucination I caught when I checked the original source."

Tamil	Hindi	Français	Korean	Japanese
AI கற்பனை / பொய் தகவல்	AI द्वारा गढ़ी गई जानकारी / भ्रम	hallucination (de l'IA)	환각 (AI가 만들어낸 거짓 정보)	ハルシネーション（AIによる虚偽情報）

Disclosure

Definition: Telling people honestly that you used a particular tool, source, or assistance. In this class: required for any AI use.

Visual cue: An open book with the cover labeled "I used AI", transparent, not hidden.

In a sentence: "Honest disclosure of AI use doesn't lower your grade; hiding AI use is an integrity violation."

Tamil	Hindi	Français	Korean	Japanese
வெளிப்படுத்துதல் / அறிவித்தல்	खुलासा करना / प्रकटन	divulgation / déclaration	공개 / 공시	開示・公表

Documentation

Definition: Recording what tools you used and how, for transparency and your own learning. In this class: the AI Documentation Template.

Visual cue: A form with fields to fill in: tool, prompts, what AI did, what I did.

In a sentence: "My AI Documentation shows I used Gemini for brainstorming and Claude for feedback, both ways the AI helped me think."

Tamil	Hindi	Français	Korean	Japanese
ஆவணப்படுத்தல்	प्रलेखन / डाक्यूमेंटेशन	documentation	기록 / 문서화	記録・文書化

Critical evaluation

Definition: Carefully examining a source's reliability, not accepting at face value, not rejecting without examination. The OPVL move in action.

Visual cue: A magnifying glass over a document.

In a sentence: "Critical evaluation of the AI source revealed that the cited 'study' didn't actually exist."

Tamil	Hindi	Français	Korean	Japanese
ஆழ்ந்த மதிப்பீடு	आलोचनात्मक मूल्यांकन	évaluation critique	비판적 평가	批判的評価

Unit 1: Earth in the Universe + Earth as a System (15 terms)

Habitability

Definition: The conditions a planet has that allow life as we know it. NOT the same as "has life": many habitable planets may not have life.

Visual cue: A checklist of conditions (water, atmosphere, temperature, etc.) with checkmarks.

In a sentence: "Earth and Mars both meet some habitability criteria; Earth has all of them, Mars has lost most."

Tamil	Hindi	Français	Korean	Japanese
வாழ்வுக்கு உகந்த தன்மை	वासयोग्यता	habitabilité	거주 가능성	居住可能性

Habitable zone (Goldilocks zone)

Definition: The orbital distance from a star where a planet could have liquid water at its surface. Named after the fairy-tale principle: not too hot, not too cold.

Visual cue: A star at center with a ring around it labeled "habitable", Earth inside, Mars at edge, Venus inside (too hot).

In a sentence: "Kepler-22 b sits in the habitable zone of a Sun-like star, but its size suggests it may not be rocky."

Tamil	Hindi	Français	Korean	Japanese
வாழ்வுக்கு உகந்த மண்டலம் (Goldilocks zone)	वासयोग्य क्षेत्र (Goldilocks zone)	zone habitable	거주 가능 영역 (골디락스 존)	ハビタブルゾーン（生命居住可能領域）

Astronomical Unit (AU)

Definition: Distance from Earth to the Sun = 149.6 million km. Used as the standard unit for measuring solar-system distances.

Visual cue: A line from the Sun to Earth labeled "1 AU."

In a sentence: "Mars orbits at 1.5 AU; the outer planets are 5–30 AU away."

Tamil	Hindi	Français	Korean	Japanese
வானியல் அலகு (AU)	खगोलीय इकाई (AU)	unité astronomique (UA)	천문 단위 (AU)	天文単位（AU）

Light-year

Definition: Distance light travels in one Earth year = ~9.5 trillion km. Used for interstellar distances.

Visual cue: A beam of light with "1 year" written along it.

In a sentence: "Proxima Centauri b is 4.2 light-years away: the closest known exoplanet."

Tamil	Hindi	Français	Korean	Japanese
ஒளி-ஆண்டு	प्रकाश-वर्ष	année-lumière	광년	光年

Exoplanet

Definition: A planet orbiting a star other than our Sun. Over 5,000 confirmed so far.

Visual cue: A small planet next to a star, labeled with a name like Kepler-22b.

In a sentence: "TRAPPIST-1 e is an exoplanet roughly Earth-sized in the habitable zone of an M-dwarf star."

Tamil	Hindi	Français	Korean	Japanese
புற-கிரகம் / எக்ஸோபிளானெட்	बहिग्र्रह / एक्सोप्लैनेट	exoplanète	외계행성	系外惑星

Transit (detection)

Definition: How we detect many exoplanets, when a planet passes in front of its star, the star's brightness dips briefly.

Visual cue: A star's brightness curve over time with a small dip in the middle.

In a sentence: "Kepler's transit method discovered thousands of exoplanets by watching for these brightness dips."

Tamil	Hindi	Français	Korean	Japanese
தாண்டல் (transit)	पारगमन / ट्रांज़िट	transit (méthode de détection)	통과 (transit) 방법	トランジット法

Atmosphere

Definition: The layer of gases surrounding a planet. Provides protection, regulates temperature, allows certain forms of life.

Visual cue: A planet with a translucent gas envelope around it.

In a sentence: "Earth's atmosphere is ~78% nitrogen and 21% oxygen; Mars's is mostly CO₂ but very thin."

Tamil	Hindi	Français	Korean	Japanese
வளிமண்டலம்	वायुमण्डल	atmosphère	대기	大気

Magnetic field

Definition: A planet's invisible force field generated by liquid iron in its core. Deflects solar wind and protects the atmosphere.

Visual cue: Curved field lines coming out of a planet's poles, deflecting incoming particles.

In a sentence: "Mars lost its magnetic field ~4 billion years ago, leading to atmospheric loss."

Tamil	Hindi	Français	Korean	Japanese
காந்தப்புலம்	चुम्बकीय क्षेत्र	champ magnétique	자기장	磁場

Subsystem (Earth)

Definition: One of Earth's four major systems: atmosphere, hydrosphere, geosphere, biosphere. They interact constantly.

Visual cue: Four circles labeled A/H/G/B, connected by arrows showing interactions.

In a sentence: "Changes in one Earth subsystem propagate to the others, climate change affects hydrology affects ecosystems."

Tamil	Hindi	Français	Korean	Japanese
துணை அமைப்பு / Earth subsystem	उप-तंत्र / Earth subsystem	sous-système (terrestre)	지구 하위 시스템 (subsystem)	地球サブシステム

Feedback loop

Definition: A cycle where the output of a process affects the process itself. Positive = amplifying; negative = stabilizing.

Visual cue: A circle of arrows with a + or − sign showing whether it amplifies or dampens.

In a sentence: "The ice-albedo feedback loop is positive: melting ice exposes darker ocean, which absorbs more heat, melting more ice."

Tamil	Hindi	Français	Korean	Japanese
உள்ளீடு / உருண்டை சுழற்சி (feedback loop)	प्रतिपुष्टि लूप	boucle de rétroaction	피드백 루프	フィードバックループ

Climate (vs. weather)

Definition: Long-term average weather conditions in a region. Weather is what's happening today; climate is what to expect over decades.

Visual cue: A timeline with daily weather (short bars) and overall climate (long average line).

In a sentence: "One hot day is weather; consistently hotter summers over 30 years is climate change."

Tamil	Hindi	Français	Korean	Japanese
காலநிலை (வானிலை அல்ல)	जलवायु (मौसम नहीं)	climat (différent de la météo)	기후 (날씨와 다름)	気候（天気とは異なる）

Systems thinking

Definition: Reasoning about how parts of a system connect and influence each other. Sees the whole, not just individual parts.

Visual cue: A diagram with nodes and arrows showing connections.

In a sentence: "Systems thinking helps us understand that fixing one part of an ecosystem can have unexpected effects elsewhere."

Tamil	Hindi	Français	Korean	Japanese
அமைப்பு சிந்தனை	तंत्र चिंतन	pensée systémique	시스템 사고	システム思考

Greenhouse effect

Definition: The way certain gases in an atmosphere trap heat, warming the planet. Natural greenhouse effect makes Earth livable; human-enhanced greenhouse effect causes warming.

Visual cue: A planet with sunlight entering, infrared bouncing back, and greenhouse gases trapping some of it.

In a sentence: "Without the greenhouse effect, Earth would be ~33°C colder and frozen."

Tamil	Hindi	Français	Korean	Japanese
பசுமை இல்ல விளைவு	ग्रीनहाउस प्रभाव	effet de serre	온실 효과	温室効果

Scale (orders of magnitude)

Definition: Comparing things by factor of 10. Saying "two orders of magnitude bigger" means 100×.

Visual cue: Powers of 10 timeline: 10, 100, 1000, etc.

In a sentence: "The universe is 10²⁶ meters across, many orders of magnitude beyond intuition."

Tamil	Hindi	Français	Korean	Japanese
அளவீடு / 10-ன் மடங்குகள்	परिमाण / दशकीय अनुपात	ordre de grandeur	규모 / 자릿수	桁・規模

Equilibrium

Definition: A state of balance where opposing forces or processes cancel out. Earth's climate was in approximate equilibrium for thousands of years until recent change.

Visual cue: A scale with equal weights on both sides.

In a sentence: "Adding too much CO₂ pushes Earth's climate out of equilibrium toward a warmer state."

Tamil	Hindi	Français	Korean	Japanese
சமநிலை	संतुलन	équilibre	평형 / 균형	平衡・均衡

Unit 2: Surface Processes & Reading the Landscape (13 terms)

Weathering (mechanical, chemical)

Definition: Breakdown of rocks at Earth's surface. Mechanical = physical breaking (frost, wind); chemical = chemical reactions (dissolution, rust).

Visual cue: Rock fragments next to a smooth piece + a rusty piece.

In a sentence: "Tropical chemical weathering is dramatic in Chennai's climate, high humidity accelerates rock breakdown."

Tamil	Hindi	Français	Korean	Japanese
சிதைதல் (இயக்க / வேதியியல்)	अपक्षय (यांत्रिक / रासायनिक)	altération (mécanique / chimique)	풍화 (기계적 / 화학적)	風化（機械的・化学的）

Erosion

Definition: Movement of weathered material by water, wind, ice, or gravity. Different from weathering (breakdown only).

Visual cue: A river carrying sediment downhill.

In a sentence: "Marina Beach erosion is mostly from waves; some segments are eroding faster than others."

Tamil	Hindi	Français	Korean	Japanese
மண்ணரிப்பு / அரிப்பு	अपरदन	érosion	침식	侵食

Deposition

Definition: Settling and accumulation of sediment in a new location after erosion. Builds beaches, deltas, river floodplains.

Visual cue: A river slowing down and depositing its load.

In a sentence: "The Cauvery delta is built from millions of years of fluvial deposition."

Tamil	Hindi	Français	Korean	Japanese
படிவு / சேமிப்பு	निक्षेपण	déposition / dépôt	퇴적	堆積

Sediment

Definition: Loose particles (sand, silt, clay) produced by weathering and transported by erosion. Becomes sedimentary rock over time.

Visual cue: Layers of sand and mud.

In a sentence: "Heavy monsoon runoff carries enormous amounts of sediment from the Western Ghats to the coast."

Tamil	Hindi	Français	Korean	Japanese
வண்டல்	अवसाद	sédiment	퇴적물	堆積物・沈殿物

Watershed

Definition: An area of land where all water drains to a single river, lake, or ocean.

Visual cue: A bowl-shaped landscape with arrows showing water flowing to a low point.

In a sentence: "The Cooum watershed is ~720 km², draining suburban + central Chennai."

Tamil	Hindi	Français	Korean	Japanese
நீர்ப்பிடிப்பு	जल विभाजन / जल ग्रहण क्षेत्र	bassin versant	유역	流域

River system

Definition: A river plus all its tributaries plus the surrounding land it drains. Operates as a connected system.

Visual cue: A branching tree of streams flowing into one main river.

In a sentence: "The Cauvery river system spans Karnataka, Tamil Nadu, Kerala, and Puducherry."

Tamil	Hindi	Français	Korean	Japanese
ஆற்று அமைப்பு	नदी प्रणाली	système fluvial	하천 시스템 / 강 유역계	河川システム

Coastal landform

Definition: Features formed where land meets sea: beaches, cliffs, bars, lagoons, estuaries.

Visual cue: Cross-section of a coast showing beach, dune, cliff.

In a sentence: "Pulicat Lake is a bar-built lagoon, a specific coastal landform."

Tamil	Hindi	Français	Korean	Japanese
கடற்கரை நிலத்தோற்றம்	तटीय भू-आकृति	forme côtière	해안 지형	海岸地形

Geomorphology

Definition: The scientific study of landscape forms and the processes that shape them.

Visual cue: A textbook with diagrams of valleys, mountains, river systems.

In a sentence: "Geomorphology helps us read landscapes, to understand the processes that made what we see."

Tamil	Hindi	Français	Korean	Japanese
நிலத்தோற்ற இயல்	भू-आकृति विज्ञान	géomorphologie	지형학	地形学

Substrate

Definition: The underlying material of a landscape, the bedrock or soil that everything else sits on.

Visual cue: Cross-section showing soil + sediment + bedrock layers.

In a sentence: "Pallikaranai Marsh sits on Holocene coastal alluvium, a young substrate that makes it wet + soft."

Tamil	Hindi	Français	Korean	Japanese
அடிப்படை பொருள் / சப்ஸ்ட்ரேட்	अधःस्तर	substrat	기질 / 기반암	基盤・基層

Bedrock

Definition: Solid rock underlying soil and sediment. The deep, stable foundation of a landscape.

Visual cue: Dark, solid rock at the bottom of a soil profile.

In a sentence: "The Eastern Ghats foothills are exposed Precambrian bedrock, among the oldest rocks in South India."

Tamil	Hindi	Français	Korean	Japanese
அடிக் கல் / பாறை	आधार-शिला	substratum rocheux / roche-mère	기반암	基岩・床岩

Topography

Definition: The shape of the land, elevation, slope, valleys, hills, plains.

Visual cue: A contour map.

In a sentence: "Chennai's topography is mostly low and flat near the coast, with the Eastern Ghats rising to the west."

Tamil	Hindi	Français	Korean	Japanese
நிலத்தோற்றம் / உயரம்-தாழ்வு	स्थलाकृति	topographie	지형 / 지세	地形・地勢

Outcrop

Definition: A place where bedrock is exposed at the surface, not hidden under soil or vegetation.

Visual cue: A rocky cliff face exposed above soil.

In a sentence: "Mahabalipuram's coastal outcrops are where Pallava-era artisans carved the rock-cut temples."

Tamil	Hindi	Français	Korean	Japanese
கல் வெளிப்படை	खुली शैल / अनावरण	affleurement	노두 (露頭)	露頭

Restoration (ecological)

Definition: Bringing back ecological function to a degraded landscape, restoring wetlands, replanting forests, recovering biodiversity.

Visual cue: Before/after photo: degraded land → restored wetland.

In a sentence: "The Adyar Estuary restoration project has been more successful than the Cooum restoration so far."

Tamil	Hindi	Français	Korean	Japanese
மீட்டுருவாக்கம் (சூழலியல்)	पारिस्थितिक पुनर्स्थापन	restauration écologique	생태 복원	生態系の修復・回復

Unit 3: Plate Tectonics & Natural Hazards (18 terms)

Plate (tectonic)

Definition: A large segment of Earth's outer shell (lithosphere) that moves slowly over the asthenosphere below. ~15 major plates cover Earth.

Visual cue: A jigsaw-puzzle map of Earth with major plates outlined.

In a sentence: "The Pacific Plate subducts beneath the Okhotsk Plate near Japan, causing megathrust earthquakes."

Tamil	Hindi	Français	Korean	Japanese
தட்டு (tectonic)	विवर्तनी प्लेट	plaque tectonique	판 (tectonic)	プレート（地殻）

Convergent boundary

Definition: Where two plates push toward each other. Produces earthquakes, mountain building (Himalayas), or subduction (volcanic arcs).

Visual cue: Two arrows pointing toward each other; one plate diving below.

In a sentence: "Japan sits on a convergent boundary where the Pacific Plate dives beneath the Okhotsk Plate."

Tamil	Hindi	Français	Korean	Japanese
ஒருங்கிணைவு எல்லை / convergent boundary	अभिसारी सीमा	frontière convergente	수렴형 경계	収束境界

Divergent boundary

Definition: Where two plates pull apart. Produces mid-ocean ridges, sea-floor spreading, rift valleys.

Visual cue: Two arrows pointing away from each other; magma rising in the gap.

In a sentence: "The Mid-Atlantic Ridge is a divergent boundary creating new ocean floor."

Tamil	Hindi	Français	Korean	Japanese
பிரிவு எல்லை / divergent boundary	अपसारी सीमा	frontière divergente	발산형 경계	発散境界

Transform boundary

Definition: Where two plates slide past each other horizontally. Produces strike-slip earthquakes (like Kobe 1995, San Andreas).

Visual cue: Two plates with horizontal arrows in opposite directions; sliding past.

In a sentence: "The Anatolian Fault under Istanbul is a transform boundary; like San Andreas, it produces shaking but no tsunamis."

Tamil	Hindi	Français	Korean	Japanese
மாற்றமைப்பு எல்லை / transform boundary	रूपांतर सीमा	frontière transformante	변환형 경계	トランスフォーム境界

Subduction

Definition: When one plate dives beneath another at a convergent boundary. Produces megathrust earthquakes, tsunamis, stratovolcanoes.

Visual cue: Cross-section showing oceanic plate sliding under continental plate.

In a sentence: "The Tōhoku 2011 megathrust earthquake was caused by subduction of the Pacific Plate."

Tamil	Hindi	Français	Korean	Japanese
உட்செலுத்துதல் (subduction)	अवतलन (subduction)	subduction	섭입 (subduction)	沈み込み（subduction）

Megathrust

Definition: A very large earthquake at a subduction zone, where the entire interface ruptures. Largest earthquakes on Earth (M9+).

Visual cue: A subduction zone with the locked interface suddenly slipping.

In a sentence: "Tōhoku 2011 (M9.1) was one of the largest megathrust events ever recorded."

Tamil	Hindi	Français	Korean	Japanese
மெகாத்ரஸ்ட் / பெரும்-தள்ளுதல்	महा-थ्रस्ट	mégathrust / méga-séisme	메가스러스트 지진	メガスラスト地震

Tsunami

Definition: A series of very long waves caused by vertical displacement of the seafloor (usually from a megathrust earthquake).

Visual cue: A wave traveling across ocean, reaching coast as a wall of water.

In a sentence: "The 2004 Indian Ocean tsunami killed ~230,000 people across 14 countries."

Tamil	Hindi	Français	Korean	Japanese
சுனாமி	सूनामी	tsunami	쓰나미	津波

Earthquake / Magnitude

Definition: Earthquake = sudden release of energy from rock movement, causing shaking. Magnitude = the size, on a logarithmic scale (M6 vs M7 = 10× bigger).

Visual cue: Seismogram showing shaking; magnitude scale showing log relationship.

In a sentence: "The M9.1 Tōhoku earthquake released ~32× more energy than an M8."

Tamil	Hindi	Français	Korean	Japanese
பூகம்பம் / அளவு	भूकंप / परिमाण	tremblement de terre / magnitude	지진 / 규모	地震・マグニチュード

Volcanism

Definition: Volcanic activity, magma rising and erupting at the surface. Different volcanoes produce different eruption types.

Visual cue: Cross-section of a volcano with magma chamber.

In a sentence: "Pinatubo's 1991 eruption was a major volcanism event that affected global climate for years."

Tamil	Hindi	Français	Korean	Japanese
எரிமலைச் செயல்பாடு	ज्वालामुखीयता	volcanisme	화산 활동	火山活動

Stratovolcano

Definition: A tall, steep-sided volcano made of alternating layers of lava and ash. Produces explosive eruptions and pyroclastic flows. (Vesuvius, Pinatubo, Merapi.)

Visual cue: Classic cone-shaped volcano with smoke.

In a sentence: "Merapi is a stratovolcano, its pyroclastic flows are the deadliest hazard."

Tamil	Hindi	Français	Korean	Japanese
அடுக்கு எரிமலை	स्ट्रैटोवोल्केनो / स्तरीय ज्वालामुखी	stratovolcan	성층 화산 / 복합 화산	成層火山

Pyroclastic flow

Definition: A fast-moving avalanche of hot gas + rock (700°C+) from a volcanic eruption. Unsurvivable up close. Engineering can't stop it; only distance + warning.

Visual cue: Volcano with red-orange cloud rushing down its side.

In a sentence: "Merapi 2010 pyroclastic flows reached 17 km from the summit, beyond the historical danger zone."

Tamil	Hindi	Français	Korean	Japanese
எரிமலை வாயு-பாறை ஓட்டம்	पाइरोक्लास्टिक प्रवाह	écoulement pyroclastique	화쇄류 / 화산쇄설류	火砕流

Liquefaction

Definition: Saturated soil behaves like a liquid when shaken violently, causing buildings to sink, tilt, or float.

Visual cue: Soil grains: orderly before shaking; suspended in water during shaking.

In a sentence: "Anchorage 1964 liquefaction caused entire neighborhoods to flow downhill into Cook Inlet."

Tamil	Hindi	Français	Korean	Japanese
திரவமாதல்	द्रवीकरण	liquéfaction	액상화	液状化

Lahar

Definition: A volcanic mudflow, water mixed with volcanic ash and rock, that can flow long distances down valleys.

Visual cue: A thick gray mud flow racing down a valley.

In a sentence: "Merapi lahars contaminated water supplies and destroyed villages downstream for years."

Tamil	Hindi	Français	Korean	Japanese
எரிமலை கசடு ஓட்டம்	ज्वालामुखी कीचड़ धारा	lahar / coulée de boue volcanique	라하르 / 화산 이류	ラハール（火山泥流）

Lithosphere / Mantle

Definition: Lithosphere = Earth's rigid outer shell (~100 km thick); contains tectonic plates. Mantle = layer below, of slowly-flowing rock that drives plate motion.

Visual cue: Cross-section of Earth showing crust + lithosphere + mantle.

In a sentence: "Plate motion is driven by convection in the mantle below the lithosphere."

Tamil	Hindi	Français	Korean	Japanese
லித்தோஸ்பியர் / மேன்டில்	स्थलमंडल / मेंटल	lithosphère / manteau	암석권 / 맨틀	リソスフェア・マントル

Engineering design

Definition: The systematic process of designing solutions to problems under constraints (budget, materials, safety).

Visual cue: An engineer at a desk with sketches + calculations + a planned structure.

In a sentence: "Engineering design for the Tectonic City Builder requires balancing budget against multiple hazards."

Tamil	Hindi	Français	Korean	Japanese
பொறியியல் வடிவமைப்பு	इंजीनियरिंग डिज़ाइन	conception d'ingénierie	공학 설계	工学設計

Hazard

Definition: A natural process that has potential to harm people or property, earthquake, tsunami, volcanic eruption, flood, drought.

Visual cue: Warning sign with various icons (earthquake, tsunami, fire).

In a sentence: "Subduction zones have multiple compounding hazards: megathrust earthquake + tsunami + liquefaction."

Tamil	Hindi	Français	Korean	Japanese
ஆபத்து	खतरा	danger / aléa	재해 / 위험	ハザード・危険

Resilience

Definition: Ability of a system (city, ecosystem, building) to absorb shock and recover. Not the same as resistance (preventing damage).

Visual cue: A bouncy ball deformed by impact, then springing back.

In a sentence: "Building resilience matters as much as building resistance, even strong cities will face some disaster damage."

Tamil	Hindi	Français	Korean	Japanese
மீள்திறன்	लचीलापन	résilience	회복력 / 복원력	レジリエンス・回復力

Simulation

Definition: A computer model that allows testing of decisions without real-world consequences. The Tectonic City Builder is a simulation.

Visual cue: A computer screen showing a city model with disaster effects.

In a sentence: "Simulation lets students iterate engineering decisions and see consequences immediately."

Tamil	Hindi	Français	Korean	Japanese
உருவகப்படுத்தல் / சிமுலேஷன்	अनुकरण / सिमुलेशन	simulation	시뮬레이션	シミュレーション

Unit 4: Atmosphere & Climate (14 terms)

Climate change

Definition: Long-term shifts in temperature and weather patterns, primarily caused by human greenhouse gas emissions since the industrial revolution.

Visual cue: Temperature graph trending upward over time, with smoke + industry icons.

In a sentence: "Climate change is making Chennai's monsoons more variable and heat waves more intense."

Tamil	Hindi	Français	Korean	Japanese
காலநிலை மாற்றம்	जलवायु परिवर्तन	changement climatique	기후 변화	気候変動

Greenhouse gas (GHG)

Definition: Atmospheric gases that trap heat, CO₂, methane, water vapor, others. Strengthens the natural greenhouse effect, causing warming.

Visual cue: Atmosphere with molecules of CO₂, CH₄ trapping outgoing heat.

In a sentence: "CO₂ is the most important long-term GHG; methane is more potent but shorter-lived."

Tamil	Hindi	Français	Korean	Japanese
பசுமை இல்ல வாயு	ग्रीनहाउस गैस	gaz à effet de serre (GES)	온실가스	温室効果ガス

Carbon cycle

Definition: The movement of carbon between atmosphere, oceans, land, and life. Includes both natural cycling and human emissions.

Visual cue: Diagram with arrows showing CO₂ moving between atmosphere, plants, ocean, soil, and underground.

In a sentence: "Human activity (fossil fuel burning) has added carbon to the atmospheric pool faster than the natural cycle can absorb it."

Tamil	Hindi	Français	Korean	Japanese
கார்பன் சுழற்சி	कार्बन चक्र	cycle du carbone	탄소 순환	炭素循環

Net-zero

Definition: Total emissions = total removals. A net-zero economy adds no net new greenhouse gases to the atmosphere.

Visual cue: A balance scale: emissions on one side, removals on the other, balanced.

In a sentence: "India has committed to net-zero by 2070; many cities aim for 2050."

Tamil	Hindi	Français	Korean	Japanese
சுத்த-பூஜ்ஜியம் (net-zero)	नेट-शून्य	neutralité carbone / zéro net	넷제로 / 탄소중립	ネットゼロ

Sequestration

Definition: Removing CO₂ from the atmosphere and storing it (in plants, soil, oceans, or technology).

Visual cue: A tree absorbing CO₂; an arrow into a long-term storage location.

In a sentence: "Mangrove sequestration is among the most concentrated forms of natural carbon storage."

Tamil	Hindi	Français	Korean	Japanese
தனிமைப்படுத்துதல் / சேமிப்பு	पृथक्करण / प्रच्छादन	séquestration	탄소 격리 / 흡수	炭素隔離・固定

Adaptation

Definition: Changes to deal with climate impacts that are already happening or will happen anyway (sea walls, heat warning systems, drought-resistant crops).

Visual cue: A city adding seawalls + tree canopy + drainage upgrades.

In a sentence: "Chennai needs adaptation strategies for monsoon flooding, heat waves, and water scarcity, climate change is already here."

Tamil	Hindi	Français	Korean	Japanese
தகவமைப்பு	अनुकूलन	adaptation	적응	適応

Mitigation

Definition: Reducing greenhouse gas emissions to limit how much climate change happens (renewable energy, efficiency, reforestation).

Visual cue: Solar panels + wind turbines + forest.

In a sentence: "Mitigation matters globally; even with full mitigation, some adaptation is still needed."

Tamil	Hindi	Français	Korean	Japanese
தணிப்பு	उपशमन	atténuation	완화 / 감축	緩和

Policy brief

Definition: A short document (~4 pages) explaining a problem to policymakers and recommending specific actions. Uses non-academic, decision-focused voice.

Visual cue: A 4-page document with executive summary, problem, evidence, recommendations sections.

In a sentence: "The Chennai Climate Brief is your policy brief addressed to the Greater Chennai Corporation."

Tamil	Hindi	Français	Korean	Japanese
கொள்கை சுருக்கம்	नीति-संक्षेप / पॉलिसी ब्रीफ	note de politique / policy brief	정책 브리프 / 정책 보고서	政策提言書（ポリシーブリーフ）

Scenario

Definition: A possible future, based on specific assumptions. IPCC scenarios (SSPs) explore different emissions + policy pathways. Not predictions.

Visual cue: Branching paths labeled SSP1-1.9, SSP2-4.5, etc.

In a sentence: "The SSP5-8.5 scenario is the worst-case high-emissions pathway; SSP1-1.9 is the most aggressive mitigation pathway."

Tamil	Hindi	Français	Korean	Japanese
சாத்திய நிலைமை / scenario	परिदृश्य / सिनारियो	scénario	시나리오	シナリオ

Projection

Definition: An estimate of future conditions based on current trends and assumptions. Not a prediction: depends on what choices we make.

Visual cue: A graph showing different future temperature lines based on different assumed actions.

In a sentence: "Climate projections show 1.5–3°C warming by 2100 depending on how quickly we mitigate."

Tamil	Hindi	Français	Korean	Japanese
திட்டமிடல் / projection	प्रक्षेपण / अनुमान	projection	예상 / 전망	予測・見通し

IPCC

Definition: Intergovernmental Panel on Climate Change. UN body that synthesizes global climate science. AR6 is the most recent assessment (2021–2023).

Visual cue: UN logo + climate report covers.

In a sentence: "IPCC AR6 confirms human responsibility for most warming since 1850 with virtual certainty."

Tamil	Hindi	Français	Korean	Japanese
IPCC (UN காலநிலை குழு)	IPCC (जलवायु परिवर्तन पर अंतर-सरकारी पैनल)	GIEC (Groupe d'experts intergouvernemental sur l'évolution du climat)	IPCC (기후변화에 관한 정부간 협의체)	IPCC（気候変動に関する政府間パネル）

Tipping point

Definition: A threshold beyond which a system shifts to a different state, often hard or impossible to reverse. (Arctic ice loss, Amazon dieback, AMOC slowdown.)

Visual cue: A ball rolling along a flat surface, then suddenly dropping over an edge.

In a sentence: "Crossing a tipping point in the Amazon would shift the rainforest to savanna, a likely permanent change."

Tamil	Hindi	Français	Korean	Japanese
முடிவு புள்ளி / tipping point	महत्वपूर्ण बिंदु / टिपिंग पॉइंट	point de bascule	티핑포인트 / 임계점	ティッピングポイント・転換点

Vulnerability

Definition: The degree to which a system is exposed to climate impacts AND lacks capacity to cope with them.

Visual cue: A house in a flood zone + an elderly resident without AC = high vulnerability.

In a sentence: "Chennai's low-income coastal residents face high vulnerability to combined heat + flood + sea-level rise."

Tamil	Hindi	Français	Korean	Japanese
பாதிக்கப்படக்கூடிய தன்மை	संवेदनशीलता	vulnérabilité	취약성	脆弱性

Anthropogenic

Definition: Caused by human activity. Anthropogenic climate change = caused by human emissions, not natural variation.

Visual cue: Human hand turning a thermostat dial.

In a sentence: "Recent warming is overwhelmingly anthropogenic, natural variation alone cannot explain it."

Tamil	Hindi	Français	Korean	Japanese
மனிதனால் ஏற்படுத்தப்பட்ட	मानवीय / मानवजनित	anthropique	인위적 / 인간 활동에 의한	人為的・人間活動による

Unit 5: Hydrosphere, Freshwater & Ocean Systems (12 terms)

Hydrosphere

Definition: All the water on, under, and above Earth's surface, oceans, lakes, rivers, groundwater, atmosphere, ice.

Visual cue: Earth with oceans + clouds + rivers + ice highlighted.

In a sentence: "The hydrosphere is one of Earth's four major subsystems."

Tamil	Hindi	Français	Korean	Japanese
நீர்மண்டலம்	जलमंडल	hydrosphère	수권 / 수계	水圏

Water cycle

Definition: Continuous movement of water through evaporation, condensation, precipitation, runoff, infiltration. Earth's water doesn't disappear: it moves.

Visual cue: Classic water cycle diagram with sun, ocean, clouds, rain, river, groundwater.

In a sentence: "Climate change is intensifying the water cycle, more evaporation, more extreme precipitation, more variability."

Tamil	Hindi	Français	Korean	Japanese
நீர் சுழற்சி	जल चक्र	cycle de l'eau	물 순환 / 수문 순환	水循環

Aquifer

Definition: An underground layer of rock or sediment that holds and transmits groundwater. Some are renewable (recharged by rain); some are not.

Visual cue: Cross-section showing soil + porous rock holding water below the water table.

In a sentence: "Bangalore's aquifer has been depleting faster than rainfall can recharge it."

Tamil	Hindi	Français	Korean	Japanese
நிலத்தடி நீர்த்தேக்கம் / aquifer	जलभृत / एक्विफर	aquifère	대수층 / 지하수 함양층	帯水層

Stakeholder

Definition: Any person or group with an interest in a decision or outcome. In water disputes: farmers, governments, communities, ecosystems.

Visual cue: Multiple people standing around a table marked "water rights."

In a sentence: "The Cauvery dispute has at least 7 major stakeholder groups with different interests."

Tamil	Hindi	Français	Korean	Japanese
பங்குதாரர்	हितधारक / स्टेकहोल्डर	partie prenante	이해관계자 / 이해당사자	ステークホルダー・利害関係者

Water rights

Definition: Legal entitlements to use water from a shared source. Frameworks vary: riparian rights (geographic), prior appropriation (first-come), tribal/indigenous rights.

Visual cue: A river with multiple users and lines defining who can take how much.

In a sentence: "Water rights for the Cauvery are defined by Tribunal awards + Supreme Court rulings."

Tamil	Hindi	Français	Korean	Japanese
நீர் உரிமைகள்	जल अधिकार	droits d'utilization de l'eau	수리권 / 물 사용권	水利権

Riparian

Definition: Relating to a river bank or the land near a river. Riparian zones are ecologically important and often legally protected.

Visual cue: A river with green vegetation along its banks.

In a sentence: "Healthy riparian zones reduce flood damage and support biodiversity."

Tamil	Hindi	Français	Korean	Japanese
ஆற்றோர / நதி-நிலம் தொடர்பான	तटीय / नदी किनारे का	riparien / riverain	강가의 / 하천변의	河岸の・河川沿いの

Allocation

Definition: Dividing a limited resource (water, energy, land) among different uses or users. Often contested + political.

Visual cue: A pie chart of water divided among agriculture, cities, industry, environment.

In a sentence: "Cauvery allocation is politically contested between Tamil Nadu + Karnataka."

Tamil	Hindi	Français	Korean	Japanese
ஒதுக்கீடு	आबंटन	allocation	할당 / 배분	配分・割り当て

Conjunctive use

Definition: Coordinated use of surface water and groundwater together for maximum sustainable yield.

Visual cue: A diagram showing pumping from groundwater + drawing from a reservoir in coordination.

In a sentence: "Conjunctive use is more sustainable than reliance on either surface or groundwater alone."

Tamil	Hindi	Français	Korean	Japanese
சேர்ந்த பயன்பாடு (surface + ground water)	संयुक्त उपयोग	utilization conjointe (eau de surface + souterraine)	병행 사용 / 통합 활용	併用利用

Sustainability

Definition: Meeting today's needs without compromising future generations' ability to meet theirs.

Visual cue: Three pillars (environment, economy, society) supporting a stable platform.

In a sentence: "Bangalore's water use is not currently sustainable, extracting faster than recharge."

Tamil	Hindi	Français	Korean	Japanese
நிலைத்தன்மை / sustainability	स्थिरता / सतत्ता	durabilité	지속가능성	持続可能性・サステナビリティ

Tribunal / Treaty

Definition: Tribunal = legal body that adjudicates disputes (like the Cauvery Tribunal). Treaty = formal agreement between countries (like the Indus Waters Treaty).

Visual cue: Two contrasting images: courtroom (tribunal) vs. signing ceremony (treaty).

In a sentence: "The Cauvery Tribunal made allocation rulings; the Indus Treaty is a country-to-country water agreement."

Tamil	Hindi	Français	Korean	Japanese
தீர்ப்பாயம் / ஒப்பந்தம்	न्यायाधिकरण / संधि	tribunal / traité	심판소 / 조약	裁判所・条約

Position (in policy sense)

Definition: A stakeholder's specific stance on a contested issue. Different from "opinion": a position is a developed argument backed by evidence.

Visual cue: Two stakeholders facing each other across a table, each holding a position paper.

In a sentence: "My Position Paper argues from the perspective of a Cauvery delta farmer, that position is rooted in specific evidence and interests."

Tamil	Hindi	Français	Korean	Japanese
நிலைப்பாடு	स्थिति / पक्ष	position	입장	立場・主張

Compromise

Definition: An agreement where each side gives up something to reach a workable outcome. Different from "winning": both sides may be partially unsatisfied.

Visual cue: Two stakeholders meeting in the middle, each giving up some demand.

In a sentence: "Real water disputes rarely have full agreement, workable compromises are often the best outcome."

Tamil	Hindi	Français	Korean	Japanese
சமரசம்	समझौता	compromis	타협	妥協・歩み寄り

Unit 6: Biosphere, Land Use & Food Systems (12 terms)

Biosphere

Definition: All living things on Earth, plus the ecosystems they inhabit. Earth's living layer.

Visual cue: Earth with green vegetation + animals + microorganisms highlighted.

In a sentence: "The biosphere is the most complex of Earth's subsystems, with millions of interacting species."

Tamil	Hindi	Français	Korean	Japanese
உயிர்மண்டலம்	जैवमंडल	biosphère	생물권	生物圏

Biodiversity

Definition: The variety of life, genetic, species, ecosystem levels. Higher biodiversity often = greater ecosystem resilience.

Visual cue: A forest with many different plant + animal species.

In a sentence: "Western Ghats is a biodiversity hotspot with thousands of endemic species."

Tamil	Hindi	Français	Korean	Japanese
உயிரியல் பல்வேறுபாடு	जैव विविधता	biodiversité	생물 다양성	生物多様性

Ecosystem

Definition: A community of organisms interacting with each other and their environment. Boundaries can be physical (a pond, a forest) or functional.

Visual cue: A pond with fish, plants, insects, water, sediment all interacting.

In a sentence: "The Cauvery delta is an ecosystem connecting rice paddies, river hydrology, and waterbird populations."

Tamil	Hindi	Français	Korean	Japanese
சூழல் அமைப்பு	पारिस्थितिकी तंत्र	écosystème	생태계	生態系

Ecosystem services

Definition: Benefits humans get from ecosystems: provisioning (food, water), regulating (climate, pollination), cultural (recreation, spirituality), supporting (soil, water cycle).

Visual cue: A forest with arrows showing benefits flowing out: food, water, pollination, climate buffer.

In a sentence: "Pallikaranai Marsh provides flood-buffer ecosystem services to southern Chennai."

Tamil	Hindi	Français	Korean	Japanese
சூழலியல் சேவைகள்	पारिस्थितिकी सेवाएं	services écosystémiques	생태계 서비스	生態系サービス

Trophic level

Definition: A position in the food chain: producers (plants), primary consumers (herbivores), secondary consumers (predators of herbivores), tertiary consumers (top predators).

Visual cue: Pyramid with plants at base, herbivores above, then predators.

In a sentence: "Eating meat puts humans at a higher trophic level than eating grains, and uses much more energy."

Tamil	Hindi	Français	Korean	Japanese
உணவு நிலை / trophic level	खाद्य स्तर / पोषी स्तर	niveau trophique	영양 단계 / 영양 수준	栄養段階

Carrying capacity

Definition: The maximum population an ecosystem can sustainably support, given its resources.

Visual cue: A graph showing population growing, then leveling off at a ceiling.

In a sentence: "Modern industrial agriculture has raised Earth's apparent carrying capacity for humans, but at long-term ecological cost."

Tamil	Hindi	Français	Korean	Japanese
தாங்கும் திறன்	धारण क्षमता	capacité de charge	환경 수용력	環境収容力

Land use

Definition: How a piece of land is used, agriculture, forest, urban, conservation. Land-use decisions are central to environmental policy.

Visual cue: A pie chart of land allocated to different uses.

In a sentence: "Iowa land use is dominated by industrial corn-soy agriculture; Western Ghats has more agroforestry."

Tamil	Hindi	Français	Korean	Japanese
நில பயன்பாடு	भूमि उपयोग	utilization des terres	토지 이용 / 토지 활용	土地利用

Monoculture vs. Agroforestry

Definition: Monoculture = growing a single crop on a large area (high yield, low biodiversity). Agroforestry = mixing crops + trees (moderate yield, higher biodiversity + resilience).

Visual cue: Side-by-side: vast field of corn vs. shaded coffee under trees.

In a sentence: "Iowa corn-soy = monoculture; Western Ghats shade coffee = agroforestry."

Tamil	Hindi	Français	Korean	Japanese
ஒற்றை பயிர் / மர-பயிர் சேர்ப்பு	एकल फसल / कृषि वानिकी	monoculture / agroforesterie	단일 작물 재배 / 농림 복합 경영	単一栽培・アグロフォレストリー

Conservation vs. Restoration

Definition: Conservation = protecting existing ecosystems. Restoration = bringing back degraded ecosystems. Both are needed.

Visual cue: Conservation = a wall around an intact forest. Restoration = green growth coming back on bare land.

In a sentence: "The Pichavaram mangroves combine conservation of intact areas + restoration of degraded zones."

Tamil	Hindi	Français	Korean	Japanese
பாதுகாப்பு / மீட்டுருவாக்கம்	संरक्षण / पुनर्स्थापन	conservation / restauration	보전 / 복원	保全・修復

Trade-off

Definition: When gaining one thing means giving up another. Real-world decisions are full of trade-offs.

Visual cue: A scale with one side rising as the other falls.

In a sentence: "Land Plans involve trade-offs, maximizing food usually reduces biodiversity."

Tamil	Hindi	Français	Korean	Japanese
சமரசம் / trade-off	व्यापार-संतुलन	compromis (trade-off)	절충 / 트레이드오프	トレードオフ・両立できない選択

Multi-objective

Definition: Trying to achieve more than one goal at the same time. Multi-objective design accepts that not all goals can be maximized.

Visual cue: Multiple targets with a single shot trying to hit all of them.

In a sentence: "The Sustainable Land Plan is a multi-objective design, balancing food + biodiversity + climate + equity."

Tamil	Hindi	Français	Korean	Japanese
பல-நோக்கம்	बहु-उद्देश्यीय	multi-objectif	다목적	多目的

Indigenous

Definition: Original inhabitants of a region. Indigenous knowledge + land rights are increasingly recognized as central to sustainability.

Visual cue: A map showing indigenous territories overlaid on a country.

In a sentence: "Indigenous land management in the Amazon often achieves better biodiversity outcomes than government-run conservation."

Tamil	Hindi	Français	Korean	Japanese
பழங்குடியினர்	स्वदेशी / आदिवासी	autochtone / indigène	원주민 / 토착민	先住民

Unit 7: Energy, Pollution & Sustainability (14 terms)

Energy vs. Power

Definition: Energy = capacity to do work (measured in Joules, kWh). Power = rate of using energy (measured in Watts, MW). Different things!

Visual cue: A bucket of water (energy) + the rate at which it pours (power).

In a sentence: "A 1000 W appliance uses 1 kWh in one hour, different units measuring different things."

Tamil	Hindi	Français	Korean	Japanese
சக்தி / திறன்	ऊर्जा / शक्ति	énergie / puissance	에너지 / 동력 (전력)	エネルギー・電力（パワー）

Watt (kWh, MW, GW, TWh)

Definition: Units of power and energy. 1 kW = 1000 W; kWh = energy used at 1 kW for 1 hour; MW = megawatt = 1 million W; GW = gigawatt = 1 billion W; TWh = terawatt-hour.

Visual cue: A scale showing W → kW → MW → GW → TW with examples.

In a sentence: "Chennai's peak electricity demand can exceed 6,000 MW, equivalent to 6,000 large household stoves running simultaneously."

Tamil	Hindi	Français	Korean	Japanese
வாட் (W, kW, MW, GW)	वॉट (W, kW, MW, GW)	watt (W, kW, MW, GW)	와트 (W, kW, MW, GW)	ワット（W, kW, MW, GW）

Renewable

Definition: Energy sources that are replenished by natural processes on human timescales: solar, wind, hydro, geothermal.

Visual cue: Sun, wind turbine, water turbine, geothermal vent.

In a sentence: "Tamil Nadu has India's largest installed wind capacity, a major renewable success story."

Tamil	Hindi	Français	Korean	Japanese
புதுப்பிக்கத்தக்க (renewable)	नवीकरणीय	renouvelable	재생 가능	再生可能

Fossil fuel

Definition: Energy sources made from ancient organic matter: coal, oil, natural gas. Finite + emit greenhouse gases.

Visual cue: Coal mine, oil rig, natural gas plant.

In a sentence: "India's electricity is still ~70% from fossil fuels (mostly coal)."

Tamil	Hindi	Français	Korean	Japanese
எரிபொருள் / fossil fuel	जीवाश्म ईंधन	combustible fossile	화석연료	化石燃料

Grid

Definition: The network of electricity infrastructure, power plants, transmission lines, substations, distribution lines, that delivers electricity.

Visual cue: A web of power lines connecting generation to homes + businesses.

In a sentence: "Chennai's electricity grid must balance supply + demand minute-by-minute."

Tamil	Hindi	Français	Korean	Japanese
மின் கட்டமைப்பு / grid	ग्रिड / विद्युत नेटवर्क	réseau électrique	전력망 / 그리드	電力網・グリッド

Demand

Definition: How much energy people want, at what time. Demand varies daily, seasonally, by sector (residential / commercial / industrial / transport).

Visual cue: A demand graph: low at night, peaking in afternoon, varying by season.

In a sentence: "Phoenix's peak demand is in summer afternoons when AC use peaks."

Tamil	Hindi	Français	Korean	Japanese
தேவை / demand	मांग	demande	수요	需要

Intermittency

Definition: When energy generation isn't constant, solar doesn't shine at night, wind doesn't blow on demand. The central challenge for renewables.

Visual cue: A graph of solar generation: high midday, zero at night.

In a sentence: "Intermittency creates the need for energy storage + flexible grids."

Tamil	Hindi	Français	Korean	Japanese
முற்றுப்படா மாறுபாடு / intermittency	आंतरायिकता / असंतत्ता	intermittence	간헐성 / 비연속성	間欠性・出力変動

Energy storage

Definition: Storing electricity to use later. Includes batteries, pumped hydro, hydrogen, thermal storage. Critical for renewable integration.

Visual cue: A battery bank or pumped-hydro reservoir storing energy.

In a sentence: "Energy storage costs have dropped 70% in a decade, enabling more renewable integration."

Tamil	Hindi	Français	Korean	Japanese
சக்தி சேமிப்பு	ऊर्जा भंडारण	stockage d'énergie	에너지 저장	エネルギー貯蔵

Transition (energy)

Definition: The shift from one energy system to another, typically from fossil fuels to renewables. Takes decades and major investment.

Visual cue: A coal plant being replaced by solar + wind + storage over time.

In a sentence: "India's energy transition will take decades; net-zero by 2070 is the national commitment."

Tamil	Hindi	Français	Korean	Japanese
சக்தி மாற்றம் / transition	ऊर्जा रूपांतरण	transition énergétique	에너지 전환	エネルギー転換

Decarbonization

Definition: Reducing carbon emissions across the economy. Different from net-zero (which includes removals): focuses on cutting emissions.

Visual cue: A graph of emissions trending downward over time.

In a sentence: "Decarbonization requires changes across electricity + industry + transport + buildings + agriculture."

Tamil	Hindi	Français	Korean	Japanese
கார்பன் குறைப்பு	डीकार्बोनाइज़ेशन / कार्बन कमी	décarbonation	탈탄소화	脱炭素化

Carbon accounting

Definition: Measuring emissions across an organization. Scope 1 = direct emissions; Scope 2 = electricity purchased; Scope 3 = supply chain.

Visual cue: Three concentric circles labeled Scope 1, 2, 3.

In a sentence: "Companies often report Scope 1+2 emissions; Scope 3 (supply chain) is harder to measure but often largest."

Tamil	Hindi	Français	Korean	Japanese
கார்பன் கணக்கீடு	कार्बन लेखांकन	comptabilité carbone	탄소 회계 / 탄소 산정	カーボン会計・炭素計算

Op-Ed

Definition: An opinion-editorial article, a short, audience-aware argument piece for general newspapers or magazines. Different from academic essay.

Visual cue: A newspaper page with an opinion column highlighted.

In a sentence: "Your Op-Ed should sound like a published newspaper op-ed, not like a school essay."

Tamil	Hindi	Français	Korean	Japanese
கருத்து கட்டுரை / op-ed	ओप-एड / विचार लेख	tribune / op-ed	오피니언 칼럼 / 오피드	オピニオン記事・論説

Equity

Definition: Fairness in how benefits + burdens are distributed. Not the same as equality (treating everyone identically); equity accounts for different needs + starting points.

Visual cue: Three figures of different heights all viewing a fence; equity = providing different boxes to all see over.

In a sentence: "Climate transition equity means not putting all costs on those least able to bear them."

Tamil	Hindi	Français	Korean	Japanese
சமத்துவம் / equity	समानता / न्यायसंगता	équité	형평성 / 공평성	公平性・公正性

Just transition

Definition: Energy transition that protects workers + communities affected by the shift away from fossil fuels. Recognizes social costs of change.

Visual cue: Coal workers transitioning to renewable energy jobs.

In a sentence: "Cape Town's coal transition requires just-transition strategies for affected mining communities."

Tamil	Hindi	Français	Korean	Japanese
நியாயமான மாற்றம் / just transition	न्यायसंगत संक्रमण	transition juste	공정 전환 / 정의로운 전환	公正な移行・ジャストトランジション