/ Dictionary / Index H histogen: Meaning and Definition of Find definitions for: his•to•gen Pronunciation: (his'tu-jun, -jen"), [key] — n. Bot. a region in a plant in which tissues differentiate. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. histocompatibility antigen histogenesis Related Content Daily Word Quiz: feline Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language