Ontogenesis \On`to*gen"e*sis\, Ontogeny \On*tog"e*ny\, n. [See {Ontology}, and {Genesis}.] (Biol.) The history of the individual development of an organism; the history of the evolution of the germ; the development of an individual organism, -- in distinction from phylogeny, or evolution of the tribe. Called also {henogenesis}, {henogeny}.