re·ac·tion

(rē-ăk′shən)

a. A response to a stimulus.

b. The state resulting from such a response.

2. A reverse or opposing action.

a. A tendency to revert to a former state.

b. Opposition to progress or liberalism; extreme conservatism.

4. Chemistry A change or transformation in which a substance decomposes, combines with other substances, or interchanges constituents with other substances.

5. Physics A nuclear reaction.

6. Physics An equal and opposite force exerted by a body against another body that is exerting a force on it.

7. The response of cells or tissues to an antigen, as in a test for immunization.

American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

reaction

(rɪˈækʃən)

1. a response to some foregoing action or stimulus

2. the reciprocal action of two things acting together

3. (Government, Politics & Diplomacy) opposition to change, esp political change, or a desire to return to a former condition or system

4. (Psychology) a response indicating a person's feelings or emotional attitude

5. (Medicine) med

a. any effect produced by the action of a drug, esp an adverse effect. Compare side effect

b. any effect produced by a substance (allergen) to which a person is allergic

6. (Chemistry) short for chemical reaction, nuclear reaction

7. (Nuclear Physics) short for chemical reaction, nuclear reaction

8. (Stock Exchange) stock exchange a sharp fall in price interrupting a general rise

reˈactional adj

Usage: Reaction is used to refer both to an instant response (her reaction was one of amazement) and to a considered response in the form of a statement (the Minister gave his reaction to the court's decision). Some people think this second use is incorrect

Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

re•ac•tion

(riˈæk ʃən)

n.

1. action in response to some influence, event, etc.: the nation's reaction to the president's speech.

a. a physiological response to an action or condition.

b. a physiological change indicating sensitivity to foreign matter: an allergic reaction.

3. an action in a reverse direction or manner.

4. a movement toward extreme political conservatism; a desire to return to an earlier system or order.

a. the reciprocal action of chemical agents upon each other; chemical change.

b. a process that, unlike a chemical reaction, has the power to change the nucleus of an atom, as radioactive decay, fission, or the like.

6. Mech. the instantaneous response of a system to an applied force, manifested as the exertion of a force equal in magnitude, but opposite in direction, to the applied force.

[1635–45; on the model of react]

re•ac′tion•al, adj.

re·ac·tion

(rē-ăk′shən)

1. A rearrangement of the atoms or molecules of two or more substances that come into contact with each other, resulting in the formation of one or more new substances. Chemical reactions are caused by electrons of one substance interacting with those of another. The reaction of an acid with a base, for example, results in the creation of a salt and water. Some, but not all, reactions can be reversed.

2. A change to the structure of an atomic nucleus; a nuclear reaction.

3. An action that results directly from or counteracts another action, especially the change in a body's motion as a result of a force applied to it. Some reactions counteract forces and are not readily apparent. When an object rests on a surface, such as a table, for example, the downward force it applies to the surface is counteracted by an equal but upwards force, or reaction, applied by the surface. See more at Newton's laws of motion.

The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

reaction

A process in which substances react to form new substances. Bonds are broken and re-formed in chemical reactions.

ThesaurusAntonymsRelated WordsSynonymsLegend:

Noun	1.	reaction - (chemistry) a process in which one or more substances are changed into others; "there was a chemical reaction of the lime with the ground water" chemical reaction chemical science, chemistry - the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions addition reaction - a chemical reaction in which one molecule is added to another aldol reaction - a reaction of aldehydes resulting in an aldol chain reaction - a series of chemical reactions in which the product of one is a reactant in the next chemical equilibrium, equilibrium - a chemical reaction and its reverse proceed at equal rates chemical action, chemical change, chemical process - (chemistry) any process determined by the atomic and molecular composition and structure of the substances involved chemical decomposition reaction, decomposition reaction, decomposition - (chemistry) separation of a substance into two or more substances that may differ from each other and from the original substance displacement reaction, displacement - (chemistry) a reaction in which an elementary substance displaces and sets free a constituent element from a compound double decomposition, double decomposition reaction, metathesis - a chemical reaction between two compounds in which parts of each are interchanged to form two new compounds (AB+CD=AD+CB) elimination reaction - a chemical reaction in which a molecule decomposes to two different molecules endothermic reaction - a chemical reaction accompanied by the absorption of heat exothermic reaction - a chemical reaction accompanied by the evolution of heat hydrolysis - a chemical reaction in which water reacts with a compound to produce other compounds; involves the splitting of a bond and the addition of the hydrogen cation and the hydroxide anion from the water neutralisation, neutralisation reaction, neutralization reaction, neutralization - a chemical reaction in which an acid and a base interact with the formation of a salt; with strong acids and bases the essential reaction is the combination of hydrogen ions with hydroxyl ions to form water oxidation, oxidisation, oxidization - the process of oxidizing; the addition of oxygen to a compound with a loss of electrons; always occurs accompanied by reduction oxidation-reduction, oxidoreduction, redox - a reversible chemical reaction in which one reaction is an oxidation and the reverse is a reduction photochemical reaction - a chemical reaction produced by the action of light reducing, reduction - any process in which electrons are added to an atom or ion (as by removing oxygen or adding hydrogen); always occurs accompanied by oxidation of the reducing agent saponification - a chemical reaction in which an ester is heated with an alkali (especially the alkaline hydrolysis of a fat or oil to make soap)
	2.	reaction - an idea evoked by some experience; "his reaction to the news was to start planning what to do" idea, thought - the content of cognition; the main thing you are thinking about; "it was not a good idea"; "the thought never entered my mind"
	3.	reaction - a bodily process occurring due to the effect of some antecedent stimulus or agent; "a bad reaction to the medicine"; "his responses have slowed with age" response automatism - any reaction that occurs automatically without conscious thought or reflection (especially the undirected behavior seen in psychomotor epilepsy) rebound - a reaction to a crisis or setback or frustration; "he is still on the rebound from his wife's death" overreaction - an excessive reaction; a reaction with inappropriate emotional behavior electrical skin response, electrodermal response, Fere phenomenon, galvanic skin response, GSR, psychogalvanic response, Tarchanoff phenomenon - a change in the electrical properties of the skin in response to stress or anxiety; can be measured either by recording the electrical resistance of the skin or by recording weak currents generated by the body immune reaction, immune response, immunologic response - a bodily defense reaction that recognizes an invading substance (an antigen: such as a virus or fungus or bacteria or transplanted organ) and produces antibodies specific against that antigen tropism - an involuntary orienting response; positive or negative reaction to a stimulus source taxis - a locomotor response toward or away from an external stimulus by a motile (and usually simple) organism kinesis - a movement that is a response to a stimulus but is not oriented with respect to the source of stimulation double take - a delayed reaction indicating surprise inborn reflex, innate reflex, instinctive reflex, physiological reaction, reflex, reflex action, reflex response, unconditioned reflex - an automatic instinctive unlearned reaction to a stimulus learned reaction, learned response - a reaction that has been acquired by learning passing, passage - a bodily reaction of changing from one place or stage to another; "the passage of air from the lungs"; "the passing of flatus" answer - a nonverbal reaction; "his answer to any problem was to get drunk"; "their answer was to sue me" transfusion reaction - reaction of the body to a transfusion of blood that is not compatible with its own blood; an adverse reaction can range from fever and hives to renal failure and shock and death bodily function, bodily process, body process, activity - an organic process that takes place in the body; "respiratory activity"
	4.	reaction - (mechanics) the equal and opposite force that is produced when any force is applied to a body; "every action has an equal and opposite reaction" mechanics - the branch of physics concerned with the motion of bodies in a frame of reference force - (physics) the influence that produces a change in a physical quantity; "force equals mass times acceleration"
	5.	reaction - a response that reveals a person's feelings or attitude; "he was pleased by the audience's reaction to his performance"; "John feared his mother's reaction when she saw the broken lamp" response - a result; "this situation developed in response to events in Africa"
	6.	reaction - extreme conservatism in political or social matters; "the forces of reaction carried the election" conservatism, conservativism - a political or theological orientation advocating the preservation of the best in society and opposing radical changes
	7.	reaction - doing something in opposition to another way of doing it that you don't like; "his style of painting was a reaction against cubism" opposition, resistance - the action of opposing something that you disapprove or disagree with; "he encountered a general feeling of resistance from many citizens"; "despite opposition from the newspapers he went ahead" backlash - an adverse reaction to some political or social occurrence; "there was a backlash of intolerance"

reaction

noun

1. response, acknowledgment, feedback, answer, reply He showed no reaction when the judge pronounced his sentence.

2. counteraction, compensation, backlash, recoil, counterbalance, counterpoise All new fashion starts out as a reaction against existing convention.

3. conservatism, the right, the extreme right, counter-revolution, obscurantism their victory against the forces of reaction and conservatism

4. sensitivity, condition, susceptibility, hypersensitivity, allergic effect Common foods which cause this kind of reaction are fish, eggs and shellfish.

Collins Thesaurus of the English Language – Complete and Unabridged 2nd Edition. 2002 © HarperCollins Publishers 1995, 2002

reaction

noun

1. An action elicited by a stimulus:

response, retroaction.

2. The way in which a machine or other thing performs or functions:

behavior, functioning, operation, performance, working (often used in plural).

Translations

تَغيير في الرأيتَفَاعُلرد فِعْلرَد فِعْل، تَفاعُل

reakcezvratodpověď

reaktion

Reaktion Rückwirkung

αντίδραση

reacción

reaktiovastatoimi

réaction répercussion réponse conséquence

reakcija

reakció

gagnverkunhvörfviîbragî

reazione

反応

반응

odziv

reaktion

ปฏิกิริยา

tepki reaksiyon

sự phản ứng

反应化学反应反作用力

reaction

[riːˈækʃən] N

1. (= response) → reacción f
what was his reaction to your suggestion? → ¿cuál fue su reacción a tu sugerencia? → ¿cómo reaccionó frente a tu sugerencia?
it produced no reaction → no surtió efecto
some foods cause allergic reactions → algunos alimentos provocan reacciones alérgicas

2. reactions (= reflexes) → reacciones fpl
his reactions were slow because he'd been drinking → tardaba en reaccionar porque había estado bebiendo

3. (Pol) (pej) → reacción f
the forces of reaction → las fuerzas de la reacción, las fuerzas reaccionarias

4. (Chem) → reacción f

Collins Spanish Dictionary - Complete and Unabridged 8th Edition 2005 © William Collins Sons & Co. Ltd. 1971, 1988 © HarperCollins Publishers 1992, 1993, 1996, 1997, 2000, 2003, 2005

reaction

[riˈækʃ^ən] n

(= response) → réaction f
The sport requires very fast reactions → Ce sport requiert des réactions très rapides.
reaction to sth → réaction à qch
a reaction against sth → une réaction contre qch

(to drug, treatment, allergen) → réaction f
reaction to sth → réaction à qch
an allergic reaction to penicillin → une réaction allergique à la pénicilline

(CHEMISTRY) → réaction f

(= opposition to change) → réaction f
the forces of reaction → les forces de la réaction

reaction

(= response, Chem, Phys) → Reaktion f (→ to auf +acc, → against gegen); what was his reaction to your suggestion? → wie hat er auf Ihren Vorschlag reagiert?, wie war seine Reaktion auf Ihren Vorschlag?; a reaction against feminism → eine Absage an den Feminismus; action and reaction → Wirkung und Gegenwirkung

(Pol) → Reaktion f; forces of reaction → reaktionäre Kräfte pl

(Mil) → Gegenschlag m

(St Ex) → Umschwung m, → Rückgang m

Collins German Dictionary – Complete and Unabridged 7th Edition 2005. © William Collins Sons & Co. Ltd. 1980 © HarperCollins Publishers 1991, 1997, 1999, 2004, 2005, 2007

reaction

[riːˈækʃ/ən] n → reazione f

react

(riˈӕkt) verb

1. to behave in a certain way as a result of something. How did he react when you called him a fool?; He reacted angrily to the criticism; Hydrogen reacts with oxygen to form water.

2. (with against) to behave or act in a certain way in order to show rejection of. Young people tend to react against their parents.

3. (with to) to be affected, usually badly, by (a drug etc). I react very badly to penicillin.

reˈaction (-ʃən) noun

1. the act of reacting. What was his reaction to your remarks?; I get a bad reaction from penicillin; I'd like to ask you for your reactions to these suggestions.

2. a change of opinions, feelings etc (usually against someone or something). The new government was popular at first, but then a reaction began.

3. a process of change which occurs when two or more substances are put together. (a) nuclear reaction; a chemical reaction between iron and acid.

reˈactionary (-ʃə-) adjective, noun

(plural reˈactionaries) (a person) opposed to change and progress or favouring a return to things as they were.

reˈactor noun

(also nuclear reactor) an apparatus in which nuclear energy is produced which can be used as a source of power, eg when converted into electricity.

reaction

→ تَفَاعُل reakce reaktion Reaktion αντίδραση reacción reaktio réaction reakcija reazione 反応 반응 reactie reaksjon reakcja reação реакция reaktion ปฏิกิริยา tepki sự phản ứng 反应

re·ac·tion

n. reacción, respuesta;

allergic ___ → ___ alérgica;

anaphylactic ___ → ___ anafiláctica;

anxiety ___ → ___ de ansiedad;

chain ___ → ___ en cadena;

conversion ___ → ___de conversión;

immune ___ → ___ inmune;

runaway ___ → ___ de escape.

reaction

n reacción f; adverse — reacción adversa; allergic — reacción alérgica; conversion — trastorno de conversión; cross — reacción cruzada; delayed — reacción tardía; grief — reacción de duelo; id — reacción ide, autoeccematización or autoeczematización f, dermatitis f por autosensibilización; polymerase chain — (PCR) reacción en cadena de la polimerasa; transfusion — reacción transfusional