- a sudden, forceful backward movement; recoil.
- a strong or violent reaction, as to some social or political change: a backlash of angry feeling among Southern conservatives within the party.
- the space between the thickness of a gear tooth and the width of the space between teeth in the mating gear, designed to allow for a film of lubricant, binding from heat expansion and eccentricity, or manufacturing inaccuracies.
- play or lost motion between loosely fitting machine parts.
- Angling. a snarled line on a reel, usually caused by a faulty cast.
verb (used without object)
- to make or undergo a backlash.
- a reaction or recoil between interacting worn or badly fitting parts in a mechanism
- the play between parts
- a sudden and adverse reaction, esp to a political or social developmenta public backlash against the government is inevitable
1815, of machinery, from back (adj.) + lash (n.). In metaphoric sense, it is attested from 1955.