auto- Look up auto- at Dictionary.com
word-forming element meaning "self, one's own, by oneself," from Greek auto- "self, one's own," combining form of autos "self, same," 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-.