(n.) Any action in resisting other action or force; counter
tendency; movement in a contrary direction; reverse action.
(n.) 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.
(n.) 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.
(n.) The force which a body subjected to the action of a force
from another body exerts upon the latter body in the opposite
direction.
(n.) Backward tendency or movement after revolution, reform,
or great progress in any direction.
