- (mechanics) 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.
- A reaction, objection or outcry, especially of a violent or abrupt nature.
"The public backlash to the proposal was quick and insistent."
- A sudden backward motion.
- The jarring or reflex motion caused in badly fitting machinery by irregularities in velocity or a reverse of motion.
- To cause or set off a backlash.
"(The addition of quotations indicative of this usage is being sought):"