Longman Dictionary of Contemporary English
The Collaborative International Dictionary
auto- \au"to-\ [Gr. ? self.]
A combining form, with the meaning of self, one's self, one's own, itself, its own.
a prefix with the meaning of self-moving, self-propelling; as, an autocar, an autocarriage, an autotruck, etc., an automobile car, carriage, truck, etc.
Douglas Harper's Etymology Dictionary
word-forming element meaning "self, one's own, by oneself," from Greek auto- "self, one's own," combining form of autos "self, same," which is of unknown origin. Before a vowel, aut-; before an aspirate, auth-. In Greek also used as a prefix to proper names, as in automelinna "Melinna herself." The opposite prefix would be allo-.
Wiktionary
pre. 1 Regarding oneself 2 (from automatic) automatic 3 (from automobile) relating to cars or the driving of cars
Usage examples of "auto-".
I look forward to the day when the LifeShield symbol is as commonplace as an auto-club sticker or a credit-card logo, when a gun-free environment is no longer a saleable curiosity, but a basic expectation, like air conditioning or handicapped accessibility.