/ Dictionary / Index L life history: Meaning and Definition of Find definitions for: life' his'tory Pronunciation: [key] — Biol. Biol. the series of living phenomena exhibited by an organism in the course of its development from inception to death. See(def. 1). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Life Guards life instinct Related Content Daily Word Quiz: agitated Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language