1.(Mech.) The distance through which one part of connected machinery, as a wheel, piston, or screw, can be moved without moving the connected parts, resulting from looseness in fitting or from wear; also, the jarring or reflex motion caused in badly fitting machinery by irregularities in velocity or a reverse of motion.
2.A strong and sudden reverse movement in a moving part of a machine.
3.A strong popular reaction serving to counter the effect of an action; used especially of adverse reactions to social or political developments.
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