autobiography n.

word-forming element meaning "self, one's own, by oneself, of oneself" (and especially, from 1895, "automobile"), from Greek autos, reflexive pronoun, "self, same," which is of unknown origin. It also was a common word-forming element in ancient Greek, as in modern English, but very few of the old words have survived the interval. In Greek, as a word-forming element, auto- had the sense of "self, one's own, of oneself ('independently'); of itself ('natural, native, not made'); just exactly; together with." Before a vowel, it became aut-; before an aspirate, auth-. In Greek it also was used as a prefix to proper names, as in automelinna "Melinna herself." The opposite prefix would be allo-.

1680s, "the histories of individual lives, as a branch of literature," probably from Medieval Latin biographia, from later Greek biographia "description of life" (which was not in classical Greek, bios alone being the word there for it), from Greek bios "life" (from PIE root *gwei- "to live") + graphia "record, account" (see -graphy).

The meaning "a history of some one person's life" is from 1791. The meaning "life course of any living being" is by 1854. No one-word verb form has become common; biographise/biographize (1800), biography (1844), biograph (1849) have been tried.