D defs.my
Entry 2 senses Webster, 1913

auto-

· au·to- · IPA /ˈɔ.tə-/
01 A combining form, with the meaning of self, one's self, one's own, itself, its own.
  1. 1.
    A combining form, with the meaning of self, one's self, one's own, itself, its own.
  2. 2.
    a prefix with the meaning of self-moving, self-propelling; as, an autocar, an autocarriage, an autotruck, etc., an automobile car, carriage, truck, etc.