Glossary
TEAS glossary
The words these questions assume you already know, in plain language. Each term lists the guides that teach it, and each guide links to the term where it first appears.
- acidAn acid releases hydrogen ions (H⁺) in water, giving a solution with a pH below 7.
- alveolusAn alveolus is one of the thin-walled air sacs at the end of the airways, where oxygen crosses into the blood and carbon dioxide crosses out.
- anatomical positionThe anatomical position is the reference standing posture — upright, facing forward, arms at the sides with the palms facing forward — from which every directional term is defined.
- antecedentAn antecedent is the noun a pronoun stands for — the thing it, which or this points back at in the sentence or the one before it.
- antibodyAn antibody is a protein a B cell releases that sticks to one specific antigen, marks it so a phagocyte can engulf it, and stops it working.
- assumptionAn assumption is the belief a claim needs in order to work, and that the passage usually leaves unstated — the missing step between the evidence and the conclusion.
- atomAn atom is the smallest unit of an element, built from a nucleus of protons and neutrons with electrons around it.
- atomic numberThe atomic number is the number of protons in an atom's nucleus; it also equals the electrons in a neutral atom.
- author purposeThe author purpose is the job a passage, or one line of it, is doing — informing, persuading, warning, recommending, explaining a process or comparing two framings — and it is named from the writing, never from the topic.
- biasBias is a leaning a passage does not admit: what it counts, what it leaves out, and whose voice it never reports.
- capillaryA capillary is the smallest blood vessel, a one-cell-thick tube that connects the arteries and the veins and is where substances move between the blood and the tissues.
- catalystA catalyst speeds up a reaction by lowering the energy it needs, and it is not used up by the reaction.
- chemical changeA chemical change makes one or more new substances; the evidence is a gas, a precipitate, a color change, or heat or light.
- circumferenceThe circumference is the distance around a circle: C = 2πr, where π is about 3.14 and r is the radius.
- connotationConnotation is the feeling a word carries beyond its dictionary meaning — why thrifty and stingy can describe the same habit and land differently.
- context clueA context clue is the word or phrase near an unfamiliar word that fixes what it means here — a definition, a restatement, a contrast, an example, or a cause and its effect.
- covalent bondA covalent bond forms when two nonmetals share pairs of electrons rather than transferring them.
- denotationDenotation is a word's plain, dictionary meaning — the sense the sentence is using when a word means nothing more than it says.
- dilutionDilution lowers a concentration by adding solvent: C₁V₁ = C₂V₂ because the amount of solute stays the same.
- editTo edit is to change how a draft is written, its punctuation, spelling and agreement, with the ideas it carries left exactly as they are.
- electronAn electron is a tiny negatively charged particle that moves around the nucleus; a neutral atom has as many as protons.
- estimateTo estimate, round each number to a named place value (nearest whole number, ten, dollar) and compute with the round numbers, then check the real answer's size against it.
- exothermicAn exothermic reaction releases energy as heat (and often light); an endothermic reaction takes energy in and cools its surroundings.
- explicitExplicit means said outright in the passage — the reader can point at the sentence that says it, even when an option paraphrases it.
- fact and opinionA stated fact is something a reader could check against a record; an opinion is a judgment, a recommendation, or the writer's own unverifiable claim about what someone else knows or intends.
- hormoneA hormone is a chemical a gland releases into the blood, which travels to the cells that answer it and changes what they do.
- impliedImplied means the passage gives the pieces and leaves the reader to join them — the claim follows from the text without being printed in it.
- inequalityAn inequality compares two expressions with <, >, ≤ or ≥; solve it like an equation, but flip the sign when you multiply or divide by a negative.
- inferenceAn inference is a conclusion the passage supports without stating it — usually one or more things the passage says that must be true for the answer to hold.
- ionAn ion is an atom (or group) with a charge, made by losing or gaining electrons; a metal loses, a nonmetal gains.
- ionic bondAn ionic bond forms when a metal transfers electrons to a nonmetal and the two opposite ions attract.
- ligamentA ligament is the band of connective tissue that ties one bone to another at a joint, holding the joint together while letting it move.
- loaded languageLoaded language is a word chosen for the judgment it carries — the writer's conclusion arriving inside the noun, before any reason is given.
- lymphocyteA lymphocyte is a white blood cell; its B and T cells run the adaptive immune response — B cells make antibodies, and T cells help the response and destroy taken-over cells.
- main ideaThe main idea is the single point the whole passage was written to deliver — what everything in it adds up to, not the first sentence or the longest one.
- mass numberThe mass number is the number of protons plus neutrons in an atom: neutrons = mass number − atomic number.
- meanThe mean, or average, is the total of a set of values divided by how many values there are.
- medianThe median is the middle value in a set, once the values are sorted; with an even count, average the two middle values.
- modeThe mode is the value that appears most often in a set. A set can have no mode, one mode, or several.
- myelin sheathThe myelin sheath is a fatty wrapping around some axons that speeds the impulse along by letting it jump between the gaps in the wrapping.
- negative feedbackNegative feedback is the loop in which the body checks a level, releases a hormone to move it back toward normal, and then slows or stops releasing the hormone once the level is back.
- neuronA neuron is a nerve cell: dendrites receive signals, the cell body sums them, and the axon carries the result away to the axon terminals.
- neutralizationNeutralization is the reaction of an acid with a base to make a salt and water, moving the pH toward 7.
- neutronA neutron is an uncharged particle in the nucleus; neutrons = mass number − atomic number.
- order of operationsThe order of operations is the agreed sequence for evaluating an expression: parentheses, then exponents, then multiply and divide left to right, then add and subtract left to right.
- percent changeA percent change is the amount of change divided by the value you started from, written as a percent: (new − old) ÷ old × 100.
- percent concentrationConcentration is how much solute is in a solution: percent concentration is the solute over the whole solution, times 100.
- periodic tableThe periodic table arranges the elements by atomic number so that columns (groups) share chemical behavior.
- peristalsisPeristalsis is the wave of muscle contractions in the wall of the digestive tube that pushes its contents onward, from the esophagus to the anus.
- pHpH measures how acidic or basic a solution is on a scale that usually runs 0–14: below 7 is acidic, 7 neutral, above 7 basic, in steps of ten.
- phagocyteA phagocyte is a white blood cell that engulfs and digests microbes and debris, acting the same way on anything foreign as part of the innate response.
- physical changeA physical change alters a substance's form, state or shape without making a new substance — melting, boiling, dissolving or cutting.
- plasmaPlasma is the liquid part of the blood: water carrying dissolved substances — nutrients, hormones, wastes, carbon dioxide and the proteins, including the clotting proteins — with the blood cells suspended in it.
- plateletA platelet is a small cell fragment in the blood that clumps at a damaged vessel wall and starts the clot that stops the bleeding.
- point of viewPoint of view is who is speaking in a passage and what that voice knows, assumes or wants — found in the pronouns and in what the passage chooses to report.
- prefixA prefix is the part fixed to the front of a word, and its job is to point that word in a direction rather than to name its subject.
- pronounA pronoun stands in for a noun the passage has already named — it, they, this, which — and what it points at is often the whole question.
- proofreadTo proofread is to read a finished piece once more, hunting what the editing pass missed: a typo, a doubled word, a quotation mark left open.
- proportionA proportion is an equation saying two ratios are equal. Solve it by keeping like units facing each other and cross-multiplying.
- protonA proton is a positively charged particle in the nucleus; its count is the atomic number and fixes the element.
- Pythagorean theoremIn a right triangle, the squares of the two legs add to the square of the hypotenuse: a² + b² = c².
- quadratic formulaThe quadratic formula solves any equation ax² + bx + c = 0: x = (−b ± √(b² − 4ac)) ÷ (2a).
- ratioA ratio compares two quantities by division, written with a colon or as a fraction — 2 to 3 means two parts of one thing for every three of another.
- reviseTo revise is to change what a draft says: the order of the ideas, the point a reader should take, the facts to add and the facts to cut.
- rootA root is the part of a word that carries its subject, the body part or idea the term is about, and that meaning does not move from term to term.
- saturated solutionA saturated solution holds all the solute it can at that temperature; an unsaturated one could still dissolve more.
- simple interestSimple interest is I = Prt — principal × rate × time — where the rate is a decimal and the time is in the rate's units.
- slopeThe slope of a line is its steepness — the rise (vertical change) divided by the run (horizontal change), or the m in y = mx + b.
- solubilitySolubility is how much of a solute will dissolve in a given amount of solvent; for most solid solutes it rises with temperature.
- soluteThe solute is the substance that dissolves in a solvent — usually the lesser amount, like the salt in salt water.
- solventThe solvent is the substance that does the dissolving — usually the greater amount, like the water in salt water.
- structural clueA structural clue is a word in the text that shows how the passage is built — a transition word, a pronoun and its antecedent, or a repeated key phrase.
- suffixA suffix is the part fixed to the end of a word, and it says what is being done or described: a condition, a procedure or a specialty.
- summaryA summary is the passage condensed to its movements — the movements are kept, the examples and figures usually dropped.
- supporting detailA supporting detail is the sentence that supports the main idea — the reason, the consequence or the example that shows the point is true.
- tendonA tendon is the cord of connective tissue that ties a muscle to a bone, so the muscle's contraction moves the bone at the joint.
- text structureText structure is how a passage is arranged — chronological, cause then effect, problem then solution, general then specific, concession then counterpoint, or claim, evidence, recommendation — and what in the wording signals that arrangement.
- toneTone is the writer's attitude toward the subject, carried by the words chosen — not by the subject itself, and not by how the passage makes you feel.
- transition wordA transition word is the hinge between sentences — because, but, unlike, then, however — naming the relationship between what you just read and what comes next.
- ureterA ureter is one of the two tubes that carry urine from a kidney down to the bladder.
- urethraThe urethra is the tube that carries urine from the bladder out of the body.
- valence electronValence electrons are the electrons in an atom's outermost shell; they decide bonding and the element's group.
- villusA villus (plural villi) is one of the finger-like folds of the small intestine's lining that give it a very large surface for absorbing the products of digestion.
- word meaning in contextWord meaning in context is the sense a word takes in the sentence in front of you — a real sense the word has, and often not its commonest one.