back·lash /ˈbækˌlæʃ/
  反斜線,后座
  backlash
  反衝
  backlash
  反衝 齒隙
  Back·lash n.
  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.
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  backlash
       n 1: a movement back from an impact [syn: recoil, repercussion,
             rebound]
       2: an adverse reaction to some political or social occurrence;
          "there was a backlash of intolerance"
       v : have an unexpected and undesired effect; "Your comments may
           backfire and cause you a lot of trouble" [syn: backfire]