jackshaft noun 2verb 1forms 3 noun2 •A common mechanical component used to transfer or synchronize rotational force in a machine. •A wheelless axle used to turn the wheels of a locomotive.Final drive is by reduction gears on the jackshaft, and through flycranks and rods to the wheels. — 1950 verb1 •To transfer or synchronize rotational force by means of a jackshaft. formsjackshafted · jackshafting · jackshafts
