Science Vocabulary: 200+ Essential Science Words with Meanings
Science has its own language. Whether you are reading a textbook, writing a lab report, preparing for IELTS Academic, or watching a documentary, you need words that do not exist in everyday English. “Photosynthesis” does not come up at dinner. “Catalyst” rarely appears in casual conversation. But in any science classroom, journal, or exam — they are everywhere.
This guide gives you 200+ essential science words organized by subject area. Each word includes a clear definition and an example sentence showing real scientific usage. The words are selected for learners who need science English for school, university, standardized tests, or professional contexts.
- Total words: 200+
- Subjects covered: General science, biology, chemistry, physics, earth science, space, environment, scientific method
- Level: B1–C1 (intermediate to advanced)
- Best for: IELTS Academic, TOEFL, university preparation, science classes in English, ESL learners
Why Science Vocabulary Matters
If you are learning English for academic purposes, science vocabulary is not optional. Here is where you will encounter it:
| Context | Why Science Words Matter |
|---|---|
| IELTS Academic Reading | 30–40% of passages are science-based (climate, biology, technology) |
| TOEFL Reading & Listening | Science lectures and articles are a core content type |
| University courses | Lectures, textbooks, and exams use technical vocabulary |
| Science documentaries | BBC, Netflix, and YouTube science content uses these words constantly |
| News & media | Climate change, health, and technology articles require science literacy |
You do not need to be a scientist. You need to recognize these words when you read them, understand them when you hear them, and use the most common ones in your own writing.
General Science Terms
These words appear across all branches of science. They are the vocabulary of scientific thinking itself.
| # | Word | Part of Speech | Meaning | Example |
|---|---|---|---|---|
| 1 | hypothesis | noun | a proposed explanation to be tested | The hypothesis predicted that plants grow faster under blue light. |
| 2 | theory | noun | a well-tested explanation supported by evidence | The theory of evolution explains how species change over time. |
| 3 | experiment | noun | a controlled test to check a hypothesis | The experiment showed that temperature affects the rate of reaction. |
| 4 | variable | noun | a factor that can change in an experiment | The independent variable was the amount of fertilizer used. |
| 5 | data | noun | facts and numbers collected during research | The data was analyzed using statistical software. |
| 6 | evidence | noun | information that supports or contradicts a claim | There is strong evidence that exercise reduces the risk of heart disease. |
| 7 | observation | noun | watching and recording something carefully | Through careful observation, Darwin noticed differences between finch beaks. |
| 8 | conclusion | noun | the final finding of a study or experiment | The conclusion was that the new drug is effective against the virus. |
| 9 | analysis | noun | the detailed study of something to understand it | A chemical analysis revealed high levels of lead in the water. |
| 10 | phenomenon | noun | an observable event, especially one that is unusual | Northern lights are a natural phenomenon caused by solar particles. |
| 11 | species | noun | a group of organisms that can breed together | Over 8 million species live on Earth, but most have not been identified. |
| 12 | sample | noun | a small part of something used for testing | The scientist collected a water sample from the river. |
| 13 | research | noun/verb | systematic study to discover new knowledge | Recent research suggests that gut bacteria affect mental health. |
| 14 | significant | adjective | large enough to have an important effect | The results showed a significant difference between the two groups. |
| 15 | accuracy | noun | how close a measurement is to the true value | The accuracy of the thermometer was tested before the experiment. |
The Scientific Method
These words describe how scientists work — from asking questions to publishing results.
| # | Word | Part of Speech | Meaning | Example |
|---|---|---|---|---|
| 16 | method | noun | a systematic way of doing something | The scientific method involves observation, hypothesis, testing, and conclusion. |
| 17 | procedure | noun | a series of steps followed in order | Follow the procedure exactly to get reliable results. |
| 18 | control group | noun | the group in an experiment that is not changed | The control group received a placebo instead of the actual drug. |
| 19 | independent variable | noun | the factor the scientist changes on purpose | The independent variable was the temperature of the water. |
| 20 | dependent variable | noun | the factor that is measured in an experiment | The dependent variable was the growth rate of the bacteria. |
| 21 | trial | noun | one run of an experiment | After 50 trials, the results were consistent. |
| 22 | replicate | verb | to repeat an experiment for reliability | Other labs could not replicate the original findings. |
| 23 | predict | verb | to state what you think will happen | The model predicts a 2°C rise in global temperatures by 2050. |
| 24 | classify | verb | to arrange into categories | Biologists classify living organisms into kingdoms, phyla, and classes. |
| 25 | measure | verb | to find the size, amount, or degree of something | We measured the pH level of each solution. |
| 26 | investigate | verb | to examine or study something carefully | Scientists are investigating the link between diet and cancer. |
| 27 | conclude | verb | to reach a decision based on evidence | The team concluded that the treatment was not effective. |
| 28 | peer review | noun | evaluation of research by other scientists | The paper was accepted after peer review by three experts. |
| 29 | bias | noun | a tendency that prevents fair judgment | Confirmation bias leads researchers to favor data that supports their hypothesis. |
| 30 | correlation | noun | a relationship between two things | There is a correlation between sleep quality and academic performance. |
Biology Vocabulary
Words for the study of living organisms — cells, genetics, ecosystems, and human body systems.
| # | Word | Part of Speech | Meaning | Example |
|---|---|---|---|---|
| 31 | cell | noun | the basic unit of all living things | The human body contains approximately 37 trillion cells. |
| 32 | organism | noun | any living thing — plant, animal, bacteria | A single-celled organism can survive in extreme environments. |
| 33 | DNA | noun | the molecule that carries genetic instructions | DNA contains the instructions for building proteins. |
| 34 | gene | noun | a unit of heredity that controls a trait | Scientists identified the gene responsible for eye color. |
| 35 | mutation | noun | a change in DNA that creates variation | A random mutation can sometimes give an organism a survival advantage. |
| 36 | evolution | noun | the gradual change in species over time | Evolution by natural selection explains the diversity of life on Earth. |
| 37 | natural selection | noun | the process where the fittest organisms survive and reproduce | Through natural selection, birds with stronger beaks survived and passed on their genes. |
| 38 | photosynthesis | noun | the process plants use to convert sunlight into food | Photosynthesis requires sunlight, water, and carbon dioxide. |
| 39 | ecosystem | noun | a community of organisms and their environment | Coral reefs are one of the most diverse ecosystems on the planet. |
| 40 | habitat | noun | the natural environment of an organism | Deforestation is destroying the habitat of thousands of species. |
| 41 | biodiversity | noun | the variety of life in a particular area | Tropical rainforests have the highest biodiversity of any land ecosystem. |
| 42 | metabolism | noun | all chemical processes inside a living organism | Your metabolism slows down as you age, which affects weight management. |
| 43 | protein | noun | a molecule made of amino acids, essential for cell function | Proteins are involved in nearly every process inside a cell. |
| 44 | bacteria | noun | single-celled organisms found everywhere | Not all bacteria are harmful — some help us digest food. |
| 45 | virus | noun | a tiny infectious agent that replicates inside cells | A virus cannot reproduce on its own — it needs a host cell. |
| 46 | immune system | noun | the body’s defense against disease | The immune system recognizes and attacks foreign invaders. |
| 47 | chromosome | noun | a structure in cells that contains DNA | Humans have 23 pairs of chromosomes. |
| 48 | respiration | noun | the process of converting food into energy | Cellular respiration releases energy from glucose. |
| 49 | reproduction | noun | the process of producing offspring | Asexual reproduction requires only one parent organism. |
| 50 | adaptation | noun | a trait that helps an organism survive in its environment | The thick fur of polar bears is an adaptation to cold climates. |
| 51 | parasite | noun | an organism that lives on or in another organism | Malaria is caused by a parasite transmitted through mosquito bites. |
| 52 | symbiosis | noun | a close, long-term relationship between two species | The relationship between clownfish and sea anemones is an example of symbiosis. |
| 53 | tissue | noun | a group of similar cells that perform a function | Muscle tissue contracts to produce movement. |
| 54 | organ | noun | a structure made of tissues that performs a specific job | The heart is an organ that pumps blood throughout the body. |
| 55 | extinct | adjective | no longer existing as a living species | Dinosaurs became extinct approximately 66 million years ago. |
Chemistry Vocabulary
Words for the study of matter, elements, reactions, and molecular structure.
| # | Word | Part of Speech | Meaning | Example |
|---|---|---|---|---|
| 56 | element | noun | a pure substance made of one type of atom | Oxygen is an element — it cannot be broken down further by chemical means. |
| 57 | compound | noun | a substance made of two or more elements bonded together | Water (H₂O) is a compound made of hydrogen and oxygen. |
| 58 | molecule | noun | two or more atoms bonded together | A molecule of carbon dioxide contains one carbon and two oxygen atoms. |
| 59 | atom | noun | the smallest unit of an element | Every atom has a nucleus surrounded by electrons. |
| 60 | reaction | noun | a process where substances change into new substances | When iron reacts with oxygen and water, the reaction produces rust. |
| 61 | catalyst | noun | a substance that speeds up a reaction without being consumed | Enzymes act as catalysts in biological reactions. |
| 62 | solution | noun | a mixture where one substance dissolves in another | Salt dissolved in water creates a solution. |
| 63 | concentration | noun | the amount of a substance in a given volume | The concentration of salt in seawater is about 3.5%. |
| 64 | acid | noun | a substance with a pH below 7 | Lemon juice is an acid with a pH of about 2. |
| 65 | base | noun | a substance with a pH above 7 | Baking soda is a base commonly used in cooking and cleaning. |
| 66 | pH | noun | a scale measuring how acidic or basic a substance is | The pH of pure water is 7, which is neutral. |
| 67 | oxidation | noun | a reaction involving the loss of electrons | Oxidation causes metals to rust when exposed to moisture. |
| 68 | bond | noun | the force that holds atoms together | A covalent bond forms when two atoms share electrons. |
| 69 | dissolve | verb | to become part of a liquid | Sugar dissolves faster in hot water than in cold water. |
| 70 | evaporate | verb | to change from liquid to gas | Water evaporates from the ocean surface and forms clouds. |
| 71 | condense | verb | to change from gas to liquid | Water vapor condenses on cold surfaces, forming droplets. |
| 72 | periodic table | noun | a chart organizing all known elements | The periodic table arranges elements by atomic number and properties. |
| 73 | isotope | noun | atoms of the same element with different numbers of neutrons | Carbon-14 is a radioactive isotope used for dating ancient materials. |
| 74 | chemical formula | noun | symbols showing the elements in a compound | The chemical formula for glucose is C₆H₁₂O₆. |
| 75 | substance | noun | any type of matter with a specific composition | The unknown substance was identified as sodium chloride. |
Physics Vocabulary
Words for the study of energy, forces, motion, and the fundamental laws of the universe.
| # | Word | Part of Speech | Meaning | Example |
|---|---|---|---|---|
| 76 | energy | noun | the capacity to do work or produce change | Solar panels convert sunlight into electrical energy. |
| 77 | force | noun | a push or pull that can change motion | Gravity is the force that pulls objects toward Earth. |
| 78 | gravity | noun | the force of attraction between objects with mass | The gravity on the Moon is about one-sixth of Earth’s gravity. |
| 79 | mass | noun | the amount of matter in an object | The mass of an object stays the same whether it is on Earth or the Moon. |
| 80 | velocity | noun | speed in a specific direction | The car’s velocity was 60 km/h heading north. |
| 81 | acceleration | noun | the rate of change in velocity | The acceleration due to gravity is approximately 9.8 m/s². |
| 82 | friction | noun | the resistance between two surfaces in contact | Friction between the tires and the road allows the car to stop. |
| 83 | momentum | noun | the product of mass and velocity | A moving truck has more momentum than a bicycle at the same speed. |
| 84 | wave | noun | a disturbance that transfers energy through matter or space | Sound travels as a wave through air, water, and solid materials. |
| 85 | frequency | noun | how often something occurs in a given time | The frequency of radio waves is measured in hertz. |
| 86 | wavelength | noun | the distance between two peaks of a wave | Visible light has a wavelength between 400 and 700 nanometers. |
| 87 | radiation | noun | energy emitted as waves or particles | The Sun emits radiation across the electromagnetic spectrum. |
| 88 | electricity | noun | the flow of electric charge | Lightning is a natural discharge of electricity. |
| 89 | magnetism | noun | a force produced by magnets or electric currents | Magnetism is used in MRI machines to create images of the body. |
| 90 | circuit | noun | a complete path through which electricity flows | If the circuit is broken, the light bulb will not turn on. |
| 91 | resistance | noun | opposition to the flow of electric current | Copper has low resistance, which makes it ideal for wiring. |
| 92 | thermodynamics | noun | the study of heat and energy transfer | The laws of thermodynamics govern how energy moves in the universe. |
| 93 | quantum | adjective/noun | relating to the smallest units of energy | Quantum mechanics describes the behavior of particles at the atomic level. |
| 94 | nuclear | adjective | relating to the nucleus of an atom | Nuclear energy is produced by splitting atoms in a process called fission. |
| 95 | spectrum | noun | the full range of something, especially light or radiation | A prism separates white light into the visible spectrum of colors. |
Earth Science Vocabulary
Words for geology, weather, climate, and the structure of our planet.
| # | Word | Part of Speech | Meaning | Example |
|---|---|---|---|---|
| 96 | atmosphere | noun | the layer of gases surrounding Earth | The atmosphere protects us from harmful solar radiation. |
| 97 | climate | noun | the long-term weather pattern of an area | The climate in Scandinavia is cold and wet for most of the year. |
| 98 | erosion | noun | the wearing away of rock or soil by water, wind, or ice | Erosion by the Colorado River carved the Grand Canyon over millions of years. |
| 99 | fossil | noun | preserved remains of ancient organisms | Scientists found a dinosaur fossil in the rock formation. |
| 100 | mineral | noun | a natural, solid substance with a specific chemical structure | Quartz is one of the most common minerals in Earth’s crust. |
| 101 | tectonic plates | noun | massive slabs of rock that form Earth’s surface | Earthquakes occur when tectonic plates collide or slide past each other. |
| 102 | volcano | noun | an opening in Earth’s surface where magma escapes | Mount Vesuvius is an active volcano near Naples, Italy. |
| 103 | earthquake | noun | a sudden shaking of the ground caused by tectonic movement | The 2011 earthquake in Japan measured 9.0 on the Richter scale. |
| 104 | sediment | noun | small particles of rock deposited by water or wind | Over time, layers of sediment compress into sedimentary rock. |
| 105 | glacier | noun | a large mass of ice that moves slowly over land | Glaciers contain about 69% of the world’s fresh water. |
| 106 | precipitation | noun | water that falls from clouds as rain, snow, or hail | Annual precipitation in the Amazon Basin exceeds 2,000 mm. |
| 107 | humidity | noun | the amount of water vapor in the air | High humidity makes hot temperatures feel even more uncomfortable. |
| 108 | drought | noun | a long period with little or no rain | The severe drought destroyed crops across the entire region. |
| 109 | latitude | noun | the distance north or south of the equator | Countries near the equator (low latitude) tend to be hotter. |
| 110 | longitude | noun | the distance east or west of the Prime Meridian | The time zone changes roughly every 15 degrees of longitude. |
Space and Astronomy Vocabulary
Words for the study of planets, stars, galaxies, and the universe.
| # | Word | Part of Speech | Meaning | Example |
|---|---|---|---|---|
| 111 | orbit | noun/verb | the path an object takes around another in space | Earth orbits the Sun once every 365.25 days. |
| 112 | galaxy | noun | a massive system of stars, gas, and dust | Our solar system is in the Milky Way galaxy, which contains over 100 billion stars. |
| 113 | solar system | noun | the Sun and all the objects that orbit it | The solar system has eight planets, from Mercury to Neptune. |
| 114 | planet | noun | a large body orbiting a star | Mars is the fourth planet from the Sun. |
| 115 | star | noun | a massive ball of hot gas that produces light and energy | The Sun is a medium-sized star about 4.6 billion years old. |
| 116 | black hole | noun | a region in space where gravity is so strong that nothing can escape | A black hole forms when a massive star collapses. |
| 117 | satellite | noun | an object that orbits a planet | The Moon is Earth’s only natural satellite. |
| 118 | telescope | noun | an instrument for observing distant objects in space | The James Webb Space Telescope captures images of galaxies billions of light-years away. |
| 119 | asteroid | noun | a small rocky body orbiting the Sun | An asteroid impact is believed to have caused the extinction of dinosaurs. |
| 120 | comet | noun | an icy body that develops a tail when near the Sun | Halley’s Comet is visible from Earth approximately every 76 years. |
| 121 | supernova | noun | the explosion of a massive star | A supernova can briefly outshine an entire galaxy. |
| 122 | light-year | noun | the distance light travels in one year (~9.46 trillion km) | The nearest star to our Sun is about 4.24 light-years away. |
| 123 | cosmic | adjective | relating to the universe | Cosmic radiation reaches Earth from distant stars and galaxies. |
| 124 | nebula | noun | a cloud of gas and dust in space | New stars are born inside nebulae when gas and dust collapse under gravity. |
| 125 | rover | noun | a vehicle designed to explore the surface of a planet | NASA’s Perseverance rover is searching for signs of ancient life on Mars. |
Environment and Ecology Vocabulary
Words for studying how humans and nature interact — climate change, conservation, and sustainability.
| # | Word | Part of Speech | Meaning | Example |
|---|---|---|---|---|
| 126 | carbon dioxide (CO₂) | noun | a greenhouse gas produced by burning fossil fuels | Carbon dioxide levels in the atmosphere have increased by 50% since 1750. |
| 127 | greenhouse effect | noun | the trapping of heat by gases in the atmosphere | The greenhouse effect is natural, but human activity has intensified it. |
| 128 | global warming | noun | the long-term rise in Earth’s average temperature | Global warming is causing sea levels to rise and ice caps to melt. |
| 129 | renewable energy | noun | energy from sources that are naturally replenished | Solar and wind are the fastest-growing forms of renewable energy. |
| 130 | fossil fuel | noun | fuel formed from ancient organisms (coal, oil, gas) | Burning fossil fuels releases carbon dioxide into the atmosphere. |
| 131 | deforestation | noun | the clearing of forests on a large scale | Deforestation in the Amazon threatens thousands of species. |
| 132 | pollution | noun | contamination of the environment with harmful substances | Air pollution causes an estimated 7 million premature deaths per year. |
| 133 | conservation | noun | the protection of natural resources and wildlife | Conservation efforts have helped the bald eagle recover from near extinction. |
| 134 | sustainability | noun | using resources without depleting them for future generations | Sustainability requires balancing economic growth with environmental protection. |
| 135 | emission | noun | the release of gas, radiation, or other substances | Governments are setting targets to reduce carbon emissions by 2030. |
| 136 | ozone layer | noun | a layer in the atmosphere that absorbs UV radiation | The ozone layer protects living organisms from harmful ultraviolet radiation. |
| 137 | endangered | adjective | at risk of extinction | The mountain gorilla is an endangered species with fewer than 1,000 remaining. |
| 138 | carbon footprint | noun | the total amount of greenhouse gases produced by a person or activity | Flying internationally significantly increases your carbon footprint. |
| 139 | recycle | verb | to convert waste into reusable material | Recycling aluminum uses 95% less energy than producing new aluminum. |
| 140 | contaminate | verb | to make something impure or poisonous | Industrial waste contaminated the local water supply. |
Medical and Health Science Vocabulary
Words for understanding the human body, diseases, and medical research.
| # | Word | Part of Speech | Meaning | Example |
|---|---|---|---|---|
| 141 | diagnosis | noun | the identification of a disease or condition | Early diagnosis of cancer significantly improves survival rates. |
| 142 | symptom | noun | a sign that indicates a disease or condition | Fever and cough are common symptoms of respiratory infections. |
| 143 | vaccine | noun | a substance that stimulates the immune system to prevent disease | The COVID-19 vaccine was developed in record time using mRNA technology. |
| 144 | antibiotic | noun | a medicine that kills bacteria | Antibiotics do not work against viruses — only against bacterial infections. |
| 145 | chronic | adjective | lasting a long time or recurring frequently | Diabetes is a chronic condition that requires lifelong management. |
| 146 | acute | adjective | severe but short-lasting | Acute appendicitis requires immediate surgery. |
| 147 | pathogen | noun | a microorganism that causes disease | Bacteria, viruses, fungi, and parasites are all types of pathogens. |
| 148 | epidemic | noun | a widespread outbreak of disease in a community | The flu epidemic affected millions of people across Europe. |
| 149 | pandemic | noun | a disease outbreak that spreads across countries or continents | The COVID-19 pandemic began in 2020 and affected every country in the world. |
| 150 | clinical trial | noun | a research study testing a new treatment on people | The drug is currently in phase 3 clinical trials with 10,000 participants. |
| 151 | genetic | adjective | relating to genes or heredity | Some diseases have a genetic component and run in families. |
| 152 | therapy | noun | treatment for a disease or condition | Gene therapy offers potential cures for diseases once considered untreatable. |
| 153 | stem cell | noun | a cell that can develop into different types of cells | Stem cell research could lead to treatments for spinal cord injuries. |
| 154 | dose | noun | the amount of medicine taken at one time | The recommended dose is two tablets every eight hours. |
| 155 | contagious | adjective | able to spread from person to person | The flu is highly contagious and spreads through coughing and sneezing. |
Technology and Applied Science Vocabulary
Words at the intersection of science and engineering — the language of innovation.
| # | Word | Part of Speech | Meaning | Example |
|---|---|---|---|---|
| 156 | algorithm | noun | a set of rules for solving a problem or making calculations | Search engines use algorithms to rank web pages by relevance. |
| 157 | artificial intelligence (AI) | noun | computer systems that perform tasks requiring human intelligence | Artificial intelligence powers voice assistants, self-driving cars, and medical diagnosis. |
| 158 | data | noun | information collected for analysis | Scientists analyzed data from over 10,000 patients to find patterns. |
| 159 | simulation | noun | a computer model that imitates a real process | Engineers ran a simulation to test how the bridge would perform in an earthquake. |
| 160 | prototype | noun | the first version of a device built for testing | The team built a prototype of the robot before starting mass production. |
| 161 | innovation | noun | a new idea, method, or technology | Innovations in battery technology are making electric vehicles more affordable. |
| 162 | biotechnology | noun | technology that uses biological systems to develop products | Biotechnology is used to develop new medicines, crops, and materials. |
| 163 | nanotechnology | noun | engineering at the scale of atoms and molecules | Nanotechnology enables drug delivery systems that target specific cells. |
| 164 | genome | noun | the complete set of genetic material in an organism | The Human Genome Project mapped all 3 billion base pairs of human DNA. |
| 165 | semiconductor | noun | a material with electrical conductivity between a conductor and an insulator | Semiconductors like silicon are the foundation of modern computer chips. |
| 166 | patent | noun | a legal right to an invention | The company filed a patent for its new solar panel design. |
| 167 | peer-reviewed | adjective | evaluated by other experts before publication | Only peer-reviewed studies should be cited in academic papers. |
| 168 | calibrate | verb | to adjust an instrument for accuracy | The telescope was calibrated before each night of observation. |
| 169 | synthesize | verb | to combine elements to create something new | Chemists synthesized a new compound with potential anti-cancer properties. |
| 170 | optimize | verb | to make something as effective as possible | Engineers optimized the engine design to reduce fuel consumption by 15%. |
Measurement and Units
Words for describing quantities, scales, and precision in science.
| # | Word | Part of Speech | Meaning | Example |
|---|---|---|---|---|
| 171 | Celsius | noun | a temperature scale where water freezes at 0° and boils at 100° | The average body temperature is approximately 37°C (Celsius). |
| 172 | Fahrenheit | noun | a temperature scale where water freezes at 32° and boils at 212° | In the United States, weather temperatures are reported in Fahrenheit. |
| 173 | kilogram | noun | the base unit of mass in the metric system | One kilogram equals approximately 2.2 pounds. |
| 174 | liter | noun | a unit of volume equal to 1,000 milliliters | The human body contains about 5 liters of blood. |
| 175 | meter | noun | the base unit of length in the metric system | The speed of light is approximately 300,000,000 meters per second. |
| 176 | microscope | noun | an instrument for viewing objects too small for the naked eye | Bacteria can only be seen through a microscope. |
| 177 | ratio | noun | the relationship between two numbers or amounts | The ratio of oxygen to nitrogen in Earth’s atmosphere is roughly 1:4. |
| 178 | density | noun | the mass per unit volume of a substance | Ice floats because its density is lower than that of liquid water. |
| 179 | volume | noun | the amount of space occupied by a substance | The volume of the container is 500 milliliters. |
| 180 | temperature | noun | a measure of how hot or cold something is | The temperature inside the reactor reached 3,000°C. |
Scientific Actions and Processes
Verbs that scientists use to describe what they do and what happens in nature.
| # | Word | Part of Speech | Meaning | Example |
|---|---|---|---|---|
| 181 | absorb | verb | to take in or soak up | Plants absorb carbon dioxide from the air during photosynthesis. |
| 182 | emit | verb | to release or send out | The factory emits 500 tons of CO₂ per year. |
| 183 | transform | verb | to change completely in form or structure | A caterpillar transforms into a butterfly during metamorphosis. |
| 184 | decay | verb | to break down naturally over time | Radioactive atoms decay at a predictable rate measured by half-life. |
| 185 | extract | verb | to remove or take out | The company extracts lithium from underground brine deposits. |
| 186 | adapt | verb | to change in order to survive in a new environment | Species that cannot adapt to climate change face extinction. |
| 187 | mutate | verb | to undergo a change in DNA | Viruses mutate rapidly, which makes vaccine development challenging. |
| 188 | erode | verb | to gradually wear away | Wind and water erode rock surfaces over thousands of years. |
| 189 | fuse | verb | to join together, especially by melting | In the Sun’s core, hydrogen atoms fuse to form helium, releasing energy. |
| 190 | oscillate | verb | to move back and forth in a regular pattern | A pendulum oscillates at a frequency determined by its length. |
| 191 | contaminate | verb | to make impure by adding a harmful substance | Chemicals from the factory contaminated the groundwater. |
| 192 | decompose | verb | to break down into simpler parts | Organic matter decomposes faster in warm, moist conditions. |
| 193 | generate | verb | to produce or create | Wind turbines generate electricity without burning fossil fuels. |
| 194 | saturate | verb | to fill completely; to dissolve the maximum amount | The solution was saturated — no more salt could dissolve. |
| 195 | conduct | verb | to transmit heat, electricity, or sound | Metals conduct electricity much better than wood or plastic. |
| 196 | insulate | verb | to prevent the transfer of heat or electricity | The walls are insulated to keep the building warm in winter. |
| 197 | dilute | verb | to make a substance less concentrated by adding water | Dilute the acid before adding it to the solution. |
| 198 | magnify | verb | to make something appear larger | The microscope can magnify objects up to 1,000 times their actual size. |
| 199 | corrode | verb | to damage metal gradually through chemical reaction | Salt water corrodes iron much faster than fresh water. |
| 200 | propagate | verb | to spread or transmit | Light waves propagate through space at 300,000 km per second. |
Vocabulary to Practice
These 25 science words frequently appear in academic texts and exams. Add them to your Linglify dictionary to practice with spaced repetition.
agreement
noun
A formal statement of shared understanding or arrangement.
Examples
- The trade agreement will benefit both countries' economic development significantly.
- There was general agreement among the committee members about the proposed changes.
budget
noun
An amount of money set aside for a specific purpose or period.
Examples
- Congress approved the new federal budget yesterday.
- The family budget allows for one vacation yearly.
contract
noun
A formal agreement or a legal document that is signed by two or more parties.
employee
noun
A person who works for a company or organization.
Examples
- Every employee receives health insurance and vacation benefits from the company.
- The dedicated employee worked overtime to complete the important project deadline.
isle
noun
A small island, often used for pleasure or as a retreat.
Examples
- Poets often write about mystical isles shrouded in morning mist.
- The small isle can be reached only by boat or helicopter.
proposal
noun
An idea or plan suggested for consideration or discussion.
Examples
- Business proposal outlines project costs and benefits.
- Marriage proposal creates emotional moment for couples.
revenue
noun
The income that a government or organization gets from taxes, sales, or other sources.
Examples
- Company revenue increases significantly during holiday season.
- Government revenue funds public services and infrastructure.
schedule
noun
A plan of things to do and when to do them, often organized in a timetable.
Examples
- Train schedule shows departure times for passengers.
- Work schedule allows flexibility for family time.
policy
noun
A set of rules or guidelines adopted by an organization or government.
Examples
- Company policy prohibits smoking in building.
- Insurance policy covers medical expenses completely.
negotiate
verb
To discuss or bargain in order to reach an agreement.
Examples
- Business partners negotiate contract terms before signing agreement.
- Diplomats negotiate peaceful solutions to international conflicts.
requirement
noun
A thing that is needed or required, often officially or formally.
Examples
- Job requirement includes relevant experience and education.
- Safety requirement protects workers from dangerous workplace.
custom
noun
A traditional way of doing things that is specific to a community or society.
Examples
- It is a local custom to remove shoes before entering homes.
- The wedding ceremony followed traditional customs from their culture.
phenomenally
adverb
In a manner that is extraordinarily impressive or remarkable.
Examples
- Sales increased phenomenally after marketing campaign launch.
- Student performed phenomenally well on challenging examination.
pay
noun
To give money in exchange for goods or services.
Examples
- Equal pay ensures fairness in workplace compensation.
- Monthly pay covers basic living expenses adequately.
solution
noun
A way to find an answer or solution to a problem.
Examples
- Chemical solution contains dissolved substances in water.
- Creative solution resolves complex business problem effectively.
complaint
noun
A statement that expresses dissatisfaction or a problem.
Examples
- She filed a formal complaint with the consumer protection agency.
- The hotel manager addressed every guest complaint promptly and professionally.
analysis
noun
The detailed examination of the parts or structure of something.
Examples
- Market analysis shows that consumer preferences are changing rapidly.
- The detailed analysis revealed several problems with the current system.
target
noun
A person or thing that is the focus of attention or effort, or an aim for achievement.
Examples
- Archery target requires precise aim and skill.
- Business target includes sales and profit goals.
performance
noun
A noun that refers to the way in which a person or thing acts or performs.
Examples
- Computer performance improves with memory upgrade.
- Evening performance received standing ovation from audience.
manager
noun
A person who is in charge of a business or organization.
Examples
- Project managers coordinate teams and ensure deadlines are met successfully.
- The store manager handles customer complaints and employee scheduling issues.
purchase
verb
To buy or obtain something, often after some effort.
Examples
- Family will purchase new car this summer.
- Online customers purchase items with credit cards.
environment
noun
The surroundings or conditions in which a person, animal, or plant lives.
Examples
- Protecting the environment is essential for future generations of people.
- The classroom environment affects how well students learn and behave.
implication
noun
A suggestion or hint about something that is not directly stated.
Examples
- Scientists are studying the implications of climate change for future generations.
- The implication of his statement was that he disagreed with the policy.
strategy
noun
A plan of action designed to achieve a long-term or overall aim.
Examples
- Chess strategy requires thinking several moves ahead.
- Marketing strategy targets specific customer demographics effectively.
How to Study Science Vocabulary Effectively
1. Learn words in subject clusters, not alphabetically. The tables above are organized by topic for a reason. Learn all 25 biology words together, then move to chemistry. Your brain creates stronger connections when words are related.
2. Use visual aids. Science vocabulary is easier to remember with diagrams. Draw the water cycle while learning “evaporate,” “condense,” and “precipitation.” Sketch a cell while learning “nucleus,” “membrane,” and “chromosome.”
3. Read science articles in English. BBC Science, National Geographic, and New Scientist are excellent sources. When you encounter a word from this list, you will reinforce it in real context.
4. Watch documentaries with subtitles. David Attenborough’s series (Planet Earth, Blue Planet) are perfect for biology and ecology vocabulary. Cosmos covers physics and astronomy. Use English subtitles and pause to note new words.
5. Write short explanations. After learning a group of words, write a 3–5 sentence paragraph using as many of them as possible: “Photosynthesis is the process by which plants absorb carbon dioxide and convert it into glucose using sunlight. This process is essential for the ecosystem because it generates the oxygen that organisms need for respiration.”
For a complete vocabulary learning system, read our guide on how to improve your vocabulary.
What to Do Next
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Build your academic vocabulary. Science words overlap heavily with the Academic Word List. Read our step-by-step vocabulary learning guide to set up a daily study system with spaced repetition.
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Prepare for IELTS Academic. Many IELTS Reading passages cover scientific topics. Our IELTS vocabulary complete guide covers all four sections.
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Learn advanced vocabulary. If you are comfortable with these science words, expand to 300+ C1–C2 advanced words for academic and professional English.
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Practice with the 4,000 essential words. Science vocabulary fits within a broader learning plan. Our 4000 essential English words guide provides a 6-month study plan.
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Apply memorization techniques. Science words can be hard to remember. Read how to memorize vocabulary for science-backed techniques including mnemonics and spaced repetition.
FAQ
What are the most important science words for IELTS?
For IELTS Academic, focus on environment and ecology vocabulary (climate, emission, sustainability, renewable energy), scientific method vocabulary (hypothesis, evidence, significant, correlation), and biology basics (species, ecosystem, evolution, adaptation). These topics appear most frequently in Reading and Listening. The 200+ words in this guide cover all commonly tested science vocabulary.
How many science words do I need to know?
For general academic English, knowing 100–150 science words is sufficient to understand most science-related texts. For university-level science courses, you need 300–500 subject-specific terms. This guide covers the 200+ most broadly useful words — the ones that appear across multiple subjects and in standardized tests.
Are these science words the same in British and American English?
Almost all science vocabulary is identical in British and American English. The few differences are in spelling (“litre” vs “liter,” “metres” vs “meters”) and some unit preferences (Celsius vs Fahrenheit). The words themselves — hypothesis, photosynthesis, catalyst — are universal.
Can I use these words in IELTS Writing?
Yes. Words like “significant,” “evidence,” “correlation,” “contribute,” and “phenomenon” are excellent for IELTS Writing Task 2, especially in essays about science, technology, environment, and health topics. For Task 1, words like “fluctuate,” “decline,” and “significant” help describe data trends. See our IELTS Writing Task 1 vocabulary guide for chart-specific vocabulary.
What is the best way to remember scientific terms?
Break words into roots. Many science words come from Latin and Greek: “photo” (light) + “synthesis” (putting together) = photosynthesis. “Bio” (life) + “diversity” = biodiversity. Learning 20–30 common roots helps you decode hundreds of science words. Combine this with spaced repetition and reading science content in English.
Do I need to memorize chemical formulas?
For general English and IELTS, no — you need to know the English names (carbon dioxide, not CO₂). For university science courses, you will need both. This guide focuses on the English vocabulary, not the formulas.
