motor: [16] The most direct English descendant of Latin movēre ‘move’ is of course move, but several more have found their way into the language via derivatives. From mōtiō ‘movement’ comes motion [15] (and its collateral forms commotion [15], emotion, and promotion [15]); from mōtīvus ‘causing to move’ come motivate [19], motive [14], and (via modern French) motif [19]; and mōtor ‘mover’ has given motor.
Originally this was used for the rather generalized notion of a ‘moving force’; the modern application to an ‘engine’ did not emerge until the mid-19th century. Also from movēre come English moment and mutiny. => commotion, emotion, moment, motif, motion, motive, move, mutiny, promotion
motor (n.)
mid-15c., "controller, prime mover," from Latin motor, literally "mover," agent noun from past participle stem of movere "to move" (see move (v.)). From 15c. as "controller, prime mover" (in reference to God); sense of "agent or force that produces mechanical motion" is first recorded 1660s; that of "machine that supplies motive power" is from 1856. First record of slang motor-mouth "fast-talking person" is from 1970.
motor (v.)
1896, from motor (n.). Related: Motored; motoring.