Relating to or of the nature of an autobiography; written by a person about their own life.
From autobiography + -al (suffix forming adjectives). The root autobiography comes from auto- (self) + bio- (life) + -graphy (writing), originating in the 1790s.
You'd think 'autobiographical' would be the main form, but 'autobiographal' exists as a rarer variant—it's like English couldn't decide which adjective form sounded better, so both stuck around in different contexts.
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