Reach"less, a. Being beyond reach; lofty.
Unto a reachless pitch of praises hight.
Bp. Hall.
Re*act" (r*kt"), v. t. To act or perform a second time; to do over
again; as, to react a play; the same scenes were reacted at Rome.
Re*act" (r*kt"), v. i. 1. To return an impulse or impression; to resist
the action of another body by an opposite force; as, every body reacts
on the body that impels it from its natural state.
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2. To act upon each other; to exercise a reciprocal or a reverse
effect, as two or more chemical agents; to act in opposition.
Re*ac"tion (r*k"shn), n. [Cf. F. réaction.] 1. Any action in resisting
other action or force; counter tendency; movement in a contrary
direction; reverse action.
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.
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.
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.
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.
Macaulay.
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.
Re*ac"tion*a*ry (-*r), a. Being, causing, or favoring reaction; as,
reactionary movements.
Re*ac"tion*a*ry, n.; pl. Reactionaries (-rz). One who favors reaction,
or seeks to undo political progress or revolution.
Re*ac"tion*ist, n. A reactionary. C. Kingsley.
Re*act"ive (r*kt"v), a. [Cf. F. réactif.] Having power to react;
tending to reaction; of the nature of reaction. -- Re*act"ive*ly, adv.
-- Re*act"ive*ness, n.