Reaction
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 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}. [1913 Webster]

3. (Med.) 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. [1913 Webster]

4. (Mech.) The force which a body subjected to the action of a force from another body exerts upon the latter body in the opposite direction. [1913 Webster]

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). [1913 Webster]

5. (Politics) Backward tendency or movement after revolution, reform, or great progress in any direction. [1913 Webster]

The new king had, at the very moment at which his fame and fortune reached the highest point, predicted the coming reaction. --Macaulay. [1913 Webster]

6. (Psycophysics) A regular or characteristic response to a stimulation of the nerves. [Webster 1913 Suppl.]

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. [PJC]

{Reaction time} (Physiol.), 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} (Mech.), 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. [1913 Webster]


The Collaborative International Dictionary of English. 2000.

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  • 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

  • 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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