'automotor' originates from a combination of Greek 'autos' (self) and Latin 'motor' (from 'movere', to move), formed in modern coinage to mean a self-moving vehicle.

'automotor' was coined in the late 19th century by combining the prefix 'auto-' (from Greek 'autos') with the Latin-derived 'motor'; similar formations appear in other European languages (e.g. French automoteur, Spanish automotor) and the word entered English usage to denote self-propelled vehicles.

Initially used broadly for anything self-moving, it came to be applied primarily to motor vehicles (automobiles) and related self-propelled rolling stock.