reaction

Noun
US[ree-ak-shuhn]/riˈækʃən/3 syllables

Open English WordNet

Noun (7)reactions

  1. (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”Synonyms: chemical reactionType of chemical process, chemical changeKinds oxidation, reduction, chain reaction, endothermic reaction, chemical equilibrium, photochemical reaction, aldol reaction, saponification, elimination reaction, neutralization +7 more
  2. an idea evoked by some experience“his reaction to the news was to start planning what to do”Type of idea, thought
  3. 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”Synonyms: responseType of bodily process, body processKinds reflex, passage, learned reaction, automatism, autonomous sensory meridian response, kinesis, galvanic skin response, transfusion reaction, taxis, rebound +5 more
  4. (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”Type of force
  5. 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”Type of response
  6. extreme conservatism in political or social matters“the forces of reaction carried the election”Type of conservatism, conservativism
  7. doing something in opposition to another way of doing it that you don't like“his style of painting was a reaction against cubism”
Word of the day · Sep 29About this word
haphazardadjective

What does it mean? Question 1 of today’s quiz

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Translations

Noun action in response to an event

Spanish
reacción
French
réaction
German
Reaktion
Italian
reazione
Portuguese
reação
Turkish
tepki
Russian
реа́кция reákcija
Arabic
رَدّ فِعْل radd fiʕl
Chinese
反应 fǎnyìng
Japanese
反応 hannō
22 more languages
Dutch
reactie
Polish
reakcja
Swedish
reaktion
Greek
αντίδραση antídrasi
Korean
반동 bandong
Vietnamese
phản ứng
Hungarian
reakció
Portuguese (PT)
reação
Chinese (Trad.)
反應 fǎnyìng
Albanian
reagim
Catalan
reacció
Czech
reakce
Danish
reaktion
Esperanto
reago
Estonian
reaktsioon
Finnish
reaktio
Georgian
რეაქცია reakcia
Hebrew
תְּגוּבָה t'guvá
Norwegian
reaksjon
Romanian
reacție
Serbo-Croatian
reakcija
Welsh
adwaith

The main translation for each meaning, from the langtolang.com multilingual dictionary. Each word links to its full entry there.

Webster's Dictionary (1913)

Re·ac′tion (rē-ăk′shŭn), noun

Origin: Cf. F. réaction.

1. Any action in resisting other action or force; counter tendency; movement in a contrary direction; reverse action.

2. Chemistry The mutual or reciprocal action of chemical agents upon each other, or the action upon such chemical agents of some form of energy, as heat, light, or electricity, resulting in a chemical change in one or more of these agents, with the production of new compounds or the manifestation of distinctive characters. See Blowpipe reaction, Flame reaction, under Blowpipe, and Flame.

3. Medicine An action induced by vital resistance to some other action; depression or exhaustion of vital force consequent on overexertion or overstimulation; heightened activity and overaction succeeding depression or shock.

4. Mechanics The force which a body subjected to the action of a force from another body exerts upon the latter body in the opposite direction.

Reaction is always equal and opposite to action, that is to say, the actions of two bodies upon each other are always equal and in opposite directions.— Sir I. Newton (3d Law of Motion).

5. Politics Backward tendency or movement after revolution, reform, or great progress in any direction.

The new king had, at the very moment at which his fame and fortune reached the highest point, predicted the coming reaction.— Thomas Babington Macaulay

6. Psycophysics A regular or characteristic response to a stimulation of the nerves.

7. An action by a person or people in response to an event. The reaction may be primarily mental (“ a reaction of surprise”) but is usually manifested by some activity.

Reaction time Physiology, in nerve physiology, the interval between the application of a stimulus to an end organ of sense and the reaction or resulting movement; — called also physiological time. — Reaction wheel Mechanics, a water wheel driven by the reaction of water, usually one in which the water, entering it centrally, escapes at its periphery in a direction opposed to that of its motion by orifices at right angles, or inclined, to its radii.

Webster’s Revised Unabridged Dictionary (1913), from GCIDE 0.54 · with additions: 1913 supplement, GCIDE editors

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