1. [syn: reaction time, response time, latency, latent period]
The Collaborative International Dictionary of English v.0.48:
Reaction \Re*ac"tion\ (r[-e]*[a^]k"sh[u^]n), n. [Cf. F.
1. Any action in resisting other action or force; counter
tendency; movement in a contrary direction; reverse
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
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.
Newton (3d Law
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.
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.
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.
WordNet (r) 3.0 (2006):
n 1: the time that elapses between a stimulus and the response
to it [syn: reaction time, response time, latency,