From The Collaborative International Dictionary of English v.0.48:
Motor car \Motor car\, or Motorcar \Mo"tor*car`\, n.
1. An automobile, locomobile, or locomotive designed to run
and be steered on a street or roadway; esp., an automobile
specially designed for passengers and propelled by an
internal combustion engine.
Syn: car, auto, automobile, machine.
[Webster 1913 Suppl.]
2. (Elec. Railroads) Any car containing motors for
propulsion. [U. S.]
[Webster 1913 Suppl.]