The Collaborative International Dictionary of English v.0.48:
Autobiography \Au`to*bi*og"ra*phy\, n.; pl. Autobiographies. [Auto- + biography.] A biography written by the subject of it; memoirs of one's life written by one's self. [1913 Webster] AutocarpousWordNet (r) 3.0 (2006):
autobiography n 1: a biography of yourself