reaction


reaction
reactional, adj.reactionally, adv.
/ree ak"sheuhn/, n.
1. a reverse movement or tendency; an action in a reverse direction or manner.
2. movement in the direction of political conservatism or extreme rightism.
3. action in response to some influence, event, etc.: the nation's reaction to the President's speech.
4. Physiol. action in response to a stimulus, as of the system or of a nerve, muscle, etc.
5. Med.
a. the action caused by the resistance to another action.
b. a return to the opposite physical condition, as after shock, exhaustion, or chill.
6. Bacteriol., Immunol. the specific cellular response to foreign matter, as in testing for allergies.
7. Chem. the reciprocal action of chemical agents upon each other; chemical change.
8. Also called nuclear reaction. Physics. a process in which a nucleus that is bombarded by a photon, particle, or other nucleus, emits a nucleon, alpha particle, or the like, without a significant change in its atomic weight.
9. 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.
10. Com. a decline in the market after an advance in prices.
[1635-45; RE- + ACTION, modeled on react]

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(as used in expressions)
reaction heat of

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Universalium. 2010.

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Look at other dictionaries:

  • réaction — [ reaksjɔ̃ ] n. f. • 1690; de re et action I ♦ Sc. 1 ♦ Mécan. Force qu un corps agissant sur un autre détermine en retour chez celui ci. Principe de l égalité de l action et de la réaction (énoncé par Newton) :un corps qui exerce sur un autre une …   Encyclopédie Universelle

  • Reaction — Réaction Cette page d’homonymie répertorie les différents sujets et articles partageant un même nom …   Wikipédia en Français

  • Reaction — Re*ac tion (r[ e]*[a^]k sh[u^]n), n. [Cf. F. r[ e]action.] 1. Any action in resisting other action or force; counter tendency; movement in a contrary direction; reverse action. [1913 Webster] 2. (Chem.) The mutual or reciprocal action of chemical …   The Collaborative International Dictionary of English

  • Réaction! — Réaction ! Réaction ! Saison 1 Épisode n°16 Titre original The Peanut Reaction Code de production 116 1e diffusion aux É. U. 12 mai 2008 …   Wikipédia en Français

  • Réaction ! — Réaction ! Saison 1 Épisode n°16 Titre original The Peanut Reaction Code de production 116 1e diffusion aux É. U. 12 mai 2008 …   Wikipédia en Français

  • reaction — Since the later part of the 20c reaction has been used to mean little more than ‘first impression’ or ‘initial response’: • ‘I became more and more infatuated with that image as I grew older,’ Rowan said and looked at me for some kind of reaction …   Modern English usage

  • reaction — (n.) 1610s, from RE (Cf. re ) again, anew + ACTION (Cf. action) (q.v.). Modeled on Fr. réaction, older It. reattione, from M.L. reactionem (nom. reactio), from L.L. react , pp. stem of reagere react, from re …   Etymology dictionary

  • reaction — I (opposition) noun backfire, backlash, challenge, clash, conflict, contradiction, contrariety, countertendency, differences, disagreement, disapprobation, discountenance, expression of disapproval, objection, offset, polarity, protest, rebound,… …   Law dictionary

  • reaction — [n1] response acknowledgment, answer, attitude, backfire, backlash, back talk*, boomerang*, comeback, compensation, counteraction, counterbalance, counterpoise, double take*, echo, feedback, feeling, hit, kick, kickback, knee jerk*, lip*, opinion …   New thesaurus

  • Reaction — (v. lat.), 1) so v.w. Gegenbewegung, Gegendruck, Gegenwirkung, d.h. eine rückwirkende Thätigkeit, welche überall stattfindet, wo entgegengesetzte Kräfte einander entgegen wirken u. sich ins Gleichgewicht zu setzen suchen. 2) Die Erscheinung, daß… …   Pierer's Universal-Lexikon

  • Reaction — Reaction, Gegenwirkung, Gegenbewegung …   Damen Conversations Lexikon


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