In linear systems, backlash and hysteresis are often referred to as the same phenomenon. But while they both contribute to lost motion, their causes and methods of operation are different.
Backlash is caused by clearance, or play, between mating parts, which introduces a dead band when the direction of travel is reversed. In the dead band, no movement occurs until the clearance between mating parts is eliminated.
Simply stated, hysteresis is the relationship between the reaction of a material to an initial load (or magnetizing force) and the material’s recovery once the load (or magnetizing force) is removed.