TOEFL Scientific Vocabulary

244 words · View all TOEFL words

Academic Reading Listening Comprehension Speaking & Writing Scientific Vocabulary

A B C D E F G H I K L M N O P R S T U V W X Z

A

accelerationthe rate of change of velocity; the second derivative of positionSAT · TOEFL acida chemical substance with pH less than 7; sharp or biting in tasteSAT · TOEFL adaptationThe process of changing to suit different conditions; an altered form of somethi…TOEFL · IELTS aerobicRelating to or requiring the presence of oxygenTOEFL aerosolTiny particles suspended in a gasTOEFL algaeSimple non-flowering plants, typically found in waterTOEFL alleleA variant of a gene that produces a different traitTOEFL alloya mixture of two or more metals; to mix metalsSAT · TOEFL amplitudethe maximum extent of variation from a center value; in waves, half the distance…SAT · TOEFL anaerobicable to live without oxygen; relating to organisms that don't require airSAT · TOEFL anatomyThe branch of science concerned with the bodily structure of organisms.SAT · TOEFL · IELTS antibodyA protein produced by the immune system to fight pathogensTOEFL antigenA substance that triggers an immune responseTOEFL aquiferAn underground layer of rock that holds waterTOEFL asteroidA small rocky body orbiting the SunTOEFL atmosphereThe pervading tone or mood of a place or situation.TOEFL · IELTS atomThe smallest unit of a chemical elementTOEFL

B

bacteriaMicroscopic single-celled organisms found in large numbers across the environmen…TOEFL · IELTS basethe number system used (e.g., base 10); the bottom side of a polygonSAT · TOEFL biodiversityThe variety of plant and animal life in the world or in a particular habitat.TOEFL · IELTS biofuelA fuel derived immediately from living matter rather than fossil fuels.TOEFL · IELTS bioluminescenceThe emission of light by living organismsTOEFL biomassThe total mass of organisms in a given area or volumeTOEFL biomeA large naturally occurring community of flora and faunaTOEFL biotechnologyThe use of living organisms in industrial or medical processesTOEFL boiling pointThe temperature at which a liquid turns to vaporTOEFL bufferA solution resisting changes in pHTOEFL

C

calibrationThe process of configuring a measuring instrumentTOEFL capillaryA very narrow tube or blood vesselTOEFL carbohydrateAn organic compound including sugars and starchesTOEFL carbon cycleThe process by which carbon is exchanged between organisms and the environmentTOEFL carbon dioxideA gas produced by burning carbon and respirationTOEFL catalystA substance that increases the rate of a reaction without being consumedGRE · SAT · TOEFL cell divisionThe process by which a cell splits into daughter cellsTOEFL cell membraneThe thin flexible boundary surrounding each cellTOEFL chemical bondAn attraction between atoms that allows chemical compounds to formTOEFL chemical reactionA process in which molecules interact and are transformedTOEFL chlorophyllThe green pigment in plants that absorbs light for photosynthesisTOEFL chromosomeA thread-like structure carrying genetic information in cellsTOEFL circulationThe continuous movement of blood through the bodyTOEFL climateThe long-term pattern of weather in an areaTOEFL combustionThe process of burning a substanceTOEFL compoundA thing that is composed of two or more separate elements; to make worse.TOEFL · IELTS condensationThe conversion of vapor into liquidTOEFL conductorA material allowing the flow of heat or electricityTOEFL conservationThe protection of the natural environment, animals, or cultural heritage.TOEFL · IELTS continentOne of the large landmasses of EarthTOEFL contractionA shortening or reduction in sizeTOEFL convectionHeat transfer through a fluid caused by movement of the fluid itselfTOEFL coreThe central part of the Earth; the center of somethingTOEFL corrosionThe gradual destruction of a material by chemical reactionTOEFL crustThe outer layer of the EarthTOEFL crystallizationThe process by which crystals form from a solution or meltTOEFL currentBelonging to the present time; a body of water or air moving in a definite direc…TOEFL · IELTS cytoplasmThe fluid that fills a cell outside the nucleusTOEFL

D

decomposeTo rot or break down into simpler substancesTOEFL decompositionThe process of decaying or breaking downTOEFL deforestationThe clearing or thinning of forests by humans.TOEFL · IELTS densityThe degree of compactness of a substance; mass per unit volumeTOEFL diffusionThe spread of molecules from higher to lower concentrationTOEFL digestionThe process by which food is broken down in the bodyTOEFL displacementThe forced movement of people from their homes or usual surroundings.TOEFL · IELTS distillationA process of purifying a liquid by evaporation and condensationTOEFL DNADeoxyribonucleic acid; the molecule carrying genetic informationTOEFL dominant geneA gene whose trait is expressed even with one copyTOEFL dormantIn a state of rest with reduced activityTOEFL droughtA prolonged period of abnormally low rainfall, leading to a shortage of water.TOEFL · IELTS

E

ecosystemA biological community of interacting organisms and their physical environment.TOEFL · IELTS electric chargeA property of matter causing it to experience electromagnetic forceTOEFL electrodeA conductor through which electricity enters or leaves an electrolyteTOEFL electrolysisChemical decomposition using an electric currentTOEFL electromagneticRelating to the interrelated phenomena of electricity and magnetismTOEFL electronA negatively charged subatomic particleTOEFL elementA component or constituent of a whole; a basic matter of a subject.TOEFL · IELTS embryoAn organism in early stages of developmentTOEFL emissionThe production and discharge of something, especially gas or radiation.TOEFL · IELTS energy transferThe movement of energy from one system to anotherTOEFL enzymeA biological molecule that catalyzes chemical reactionsTOEFL erosionThe gradual destruction or diminution of something; the wearing away of rock or …TOEFL · IELTS estuaryA coastal area where a river meets the seaTOEFL eukaryoteAn organism whose cells contain a nucleusTOEFL evaporationThe process of turning from liquid to vaporTOEFL evapotranspirationWater loss from land through evaporation and plant transpirationTOEFL evolutionThe gradual development of something into a more complex or better form.TOEFL · IELTS excretionThe process of expelling waste products from the bodyTOEFL extinctNo longer in existenceTOEFL extinctionThe state or process of being eliminated; a species ceasing to exist.TOEFL · IELTS

F

fermentationA metabolic process converting sugars to acids or alcoholTOEFL fertilizationThe fusion of gametes to produce a new organismTOEFL filtrationThe process of removing particles from a mixture using a filterTOEFL fissionThe splitting of an atomic nucleus releasing energyTOEFL flood plainFlat land adjacent to a river liable to floodingTOEFL food chainA series showing who eats whom in an ecosystemTOEFL food webAn interconnected network of food chainsTOEFL forceAn influence causing an object to change motionTOEFL fossilThe remains of a prehistoric organism preserved in rock; outdated.TOEFL · IELTS fossil fuelA natural fuel such as coal, oil, or natural gas, formed over millions of years.TOEFL · IELTS frequencyThe rate at which a vibration occurs; number of cycles per secondTOEFL · IELTS frictionThe resistance when one object moves over anotherTOEFL fungusA spore-producing organism feeding on organic matterTOEFL fusionThe process of joining atomic nuclei to release energyTOEFL

G

galaxyA system of millions of stars bound by gravityTOEFL gene expressionThe process by which instructions in DNA produce proteinsTOEFL genomeThe complete set of genes or genetic material in an organismTOEFL geologyThe science which deals with the physical structure and substance of the earth.TOEFL · IELTS geosphereThe solid rocky portion of the EarthTOEFL germinationThe process by which a seed begins to growTOEFL glacierA slowly moving mass of ice formed by the accumulation and compaction of snow.TOEFL · IELTS glucoseA simple sugar that is the primary energy source for cellsTOEFL gravityExtreme importance or seriousness; also, the force that attracts a body toward a…GRE · TOEFL greenhouse gasA gas that contributes to the greenhouse effect by absorbing infrared radiation.TOEFL · IELTS

H

habitatThe natural home or environment of an animal, plant, or other organism.TOEFL · IELTS half-lifeThe time for half a radioactive substance to decayTOEFL heredityThe passing on of physical or mental characteristics geneticallyTOEFL homeostasisThe maintenance of stable internal conditions in a living organismTOEFL hormoneA chemical messenger produced in the bodyTOEFL hydrocarbonA compound of hydrogen and carbon found in fossil fuelsTOEFL hydrosphereAll the water on Earth's surfaceTOEFL hypothesis testingThe statistical process of evaluating a research hypothesisTOEFL

I

immune responseThe body's reaction to antigensTOEFL immune systemThe body's defense against infection and diseaseTOEFL inertiatendency to remain unchanged; resistance to change or motionSAT · TOEFL infectionThe invasion of the body by pathogensTOEFL infraredElectromagnetic radiation with wavelengths longer than visible lightTOEFL inheritedReceived genetically from one's ancestorsTOEFL insulationMaterial preventing heat, electricity, or sound from passing throughTOEFL interspecificOccurring between different speciesTOEFL invasive speciesA non-native organism that disrupts its new ecosystemTOEFL ionAn atom or molecule with a net electric chargeTOEFL ionizationThe process of turning an atom into an ionTOEFL isotopeA variant of an element with a different number of neutronsTOEFL

K

kinetic energyEnergy an object possesses due to its motionTOEFL kineticsThe branch of chemistry studying the rates of reactionsTOEFL

L

larvaAn immature form of an insect or other animalTOEFL larynxThe voice box; part of the respiratory tractTOEFL light-yearThe distance light travels in one year, about 9.46 trillion kilometersTOEFL lipidA class of organic compounds including fats and oilsTOEFL lithosphereThe solid outer part of the Earth including the crustTOEFL

M

magmaMolten rock beneath the Earth's surfaceTOEFL magnetic fieldA region around a magnetic material where magnetic force actsTOEFL mantleThe layer of the Earth between the crust and coreTOEFL massA measure of the amount of matter in an object, typically measured in kilograms …GRE · TOEFL mass extinctionAn event in which a large proportion of species die outTOEFL matterPhysical substance; a subject or situation under consideration; to be important.TOEFL · IELTS meiosisCell division producing four genetically different daughter cellsTOEFL membraneA thin pliable sheet of tissue or materialTOEFL metabolismThe chemical processes that maintain life in an organismTOEFL meteorologyThe scientific study of the atmosphere and weatherTOEFL microbiologyThe study of microorganismsTOEFL microscopyThe use of microscopes to view objects too small for the naked eyeTOEFL migrationSeasonal movement of animals from one region to another; movement of people to s…TOEFL · IELTS mineralA solid inorganic substance found in the earth with a definite chemical composit…TOEFL · IELTS mitochondriaOrganelles that generate energy for the cellTOEFL mitosisCell division producing two identical daughter cellsTOEFL moleculeA group of atoms bonded together; the smallest fundamental unit of a compound.TOEFL · IELTS momentumThe impetus gained by a moving object; the increasing strength or force of somet…TOEFL · IELTS mutationA change in the DNA sequence of a geneTOEFL

N

natural selectionThe process by which traits that aid survival become more commonTOEFL neuralRelating to the nervous systemTOEFL neuronA nerve cell that transmits electrical signalsTOEFL neutronA subatomic particle with no electric charge found in the nucleusTOEFL nicheThe role and position of an organism in its ecosystemTOEFL nitrogen cycleThe process by which nitrogen is converted between formsTOEFL nocturnalDone, occurring, or active at night.TOEFL · IELTS nucleusThe central part of an atom or cell containing genetic materialTOEFL nutrientA substance that provides nourishment essential for growth and the maintenance o…TOEFL · IELTS

O

oceanographyThe scientific study of the seaTOEFL offspringA person's child or children; the young of an animal.TOEFL · IELTS orbitThe curved path of a celestial object around a star, planet, or moon.TOEFL · IELTS organA part of an organism with a specific vital functionTOEFL organicRelating to carbon compounds; produced without synthetic chemicalsTOEFL organismAn individual animal, plant, or single-celled life form.TOEFL · IELTS osmosisThe movement of water through a semipermeable membraneTOEFL oxidationA chemical reaction in which an atom loses electronsTOEFL oxygenA chemical element forming about 21% of the earth's atmosphere, essential for li…TOEFL · IELTS ozoneA form of oxygen found in the upper atmosphereTOEFL

P

pandemicA disease prevalent throughout an entire country, continent, or the whole world.TOEFL · IELTS parasiteAn organism that lives in or on a host organism and benefits at the host's expen…SAT · TOEFL · IELTS pHA scale measuring acidity or alkalinityTOEFL photonA particle of light or other electromagnetic radiationTOEFL photosynthesisThe process by which plants use sunlight, water, and CO2 to produce food.TOEFL · IELTS physicsThe branch of science concerned with matter, energy, and their interactionsTOEFL pigmentA substance giving color to tissues or cellsTOEFL plasmaThe liquid component of blood; a state of matterTOEFL plate tectonicsThe theory that Earth's crust is divided into moving platesTOEFL pollinationThe transfer of pollen from stamens to the stigma of a plantTOEFL polymerA large molecule made of repeating structural unitsTOEFL populationA group of organisms of the same species living in the same areaTOEFL potential energyStored energy that an object has due to its positionTOEFL precipitationRain, snow, or hail; the formation of a solid from a solutionTOEFL predatorAn animal that naturally preys on others; a person or organisation that exploits…TOEFL · IELTS pressureThe use of persuasion, influence, or intimidation to make someone do something; …TOEFL · IELTS preyAn animal hunted and killed by another for food; a victim.TOEFL · IELTS prokaryoteA single-celled organism without a distinct nucleusTOEFL proteinA class of nitrogenous organic compounds essential to living organisms.TOEFL · IELTS protein synthesisThe process by which cells produce proteinsTOEFL protonA positively charged subatomic particle in the nucleusTOEFL

R

radiationEnergy emitted as waves or particles through space or a mediumTOEFL radioactiveEmitting or relating to the emission of radiation from the nucleus of an atom.TOEFL · IELTS reactionA process in which substances are changed into different substancesTOEFL recessive geneA gene expressed only when two copies are presentTOEFL recycleTo convert waste into reusable material.TOEFL · IELTS reflexAn automatic response to a stimulusTOEFL refractionThe bending of light as it passes through a different mediumTOEFL renewableAble to be replenished naturally and therefore sustainable over the long term.TOEFL · IELTS renewable energyEnergy from naturally replenished sourcesTOEFL reproductionThe process by which organisms produce offspringTOEFL respirationThe process by which organisms release energy from foodTOEFL ribosomeA cell organelle that synthesizes proteinsTOEFL

S

sedimentMatter that settles to the bottom of a liquid; material deposited by water or wi…TOEFL · IELTS sedimentary rockRock formed from compressed sediment layersTOEFL seismicOf enormous proportions or effect; relating to a sudden and dramatic upheaval.GRE · TOEFL · IELTS solar systemThe Sun and all celestial bodies orbiting itTOEFL soluteA substance dissolved in a solutionTOEFL speciesA group of living organisms consisting of similar individuals capable of interbr…TOEFL · IELTS spectrumA range of values or wavelengthsTOEFL static electricityElectric charge built up on a surfaceTOEFL stimulusA thing or event that evokes a specific functional reaction; something that caus…TOEFL · IELTS subatomicSmaller than or occurring within an atomTOEFL sublimationThe transition from solid directly to gasTOEFL surface tensionThe cohesive force acting at the surface of a liquidTOEFL sustainableAble to be maintained at a certain rate or level without exhausting natural reso…TOEFL · IELTS symbiosisA close interaction between two different organismsTOEFL

T

taxonomyThe branch of science concerned with classification of organismsTOEFL tectonicRelating to the structure of the Earth's crustTOEFL temperatureThe degree of heat present in a substance or bodyTOEFL thermalRelating to heat; designed to provide insulation against cold.TOEFL · IELTS tidalRelating to or affected by tides.TOEFL · IELTS tissueA group of cells with a similar structure performing a specific functionTOEFL toxinA poisonous substance produced by a living organismTOEFL transpirationThe process by which plants release water vapor through leavesTOEFL trophic levelA position in a food chainTOEFL turbineA machine in which energy is produced by the rotation of a wheel driven by water…TOEFL · IELTS

U

ultravioletElectromagnetic radiation with a wavelength shorter than visible light but longe…TOEFL · IELTS

V

vaccineA biological preparation providing immunity to a diseaseTOEFL vascularRelating to blood vessels or plant vesselsTOEFL velocityThe rate of change of an object's position with respect to time, including both …GRE · TOEFL · IELTS vibrationAn oscillation of the parts of a fluid or an elastic solid; quivering movement.TOEFL · IELTS virusA microscopic infectious agent that replicates inside cellsTOEFL viscosityThe resistance of a fluid to flowTOEFL

W

wavelengthThe distance between two successive wave peaksTOEFL weatheringThe gradual breakdown of rock by atmospheric conditionsTOEFL

X

xylemPlant tissue that conducts water from roots to leavesTOEFL

Z

zoologyThe scientific study of animalsTOEFL