The Probert Encyclopaedia of Science & Technology

BACKLASH

In mechanics, the term backlash describes the distance through which one part of connected machinery, such as a wheel, piston, or screw, can be moved without moving the connected parts, resulting from looseness in fitting or from wear. The term also describes the jarring or reflex motion caused in badly fitting machinery by irregularities in velocity or a reverse of motion.
Research Backlash