Backlash Back"lash` (b[a^]k"l[a^]sh`), n. [Back, adv. + lash.]
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
3. A strong popular reaction serving to counter the effect of
an action; -- used especially of adverse reactions to
social or political developments.
From The Collaborative International Dictionary of English v.0.44