backlash
B2Noun/US /bˈæklˌæʃ/ BĂKL-ăsh; UK /bˈæklˌæʃ/ BĂKL-ăsh/
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 machine
