From The Collaborative International Dictionary of English v.0.48 [gcide]:
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.
From WordNet (r) 3.0 (2006) [wn]:
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