Main Entry: or·tho·gen·e·sis

Pronunciation: \ˌȯr-thə-ˈje-nə-səs\

Function: noun

Etymology: New Latin

Date: 1895

: variation of organisms in successive generations that in some especially former evolutionary theories takes place in some predestined direction resulting in progressive evolutionary trends independent of external factors

— or·tho·ge·net·ic \-jə-ˈne-tik\ adjective

— or·tho·ge·net·i·cal·ly \-ti-k(ə-)lē\ adverb