preformation

pre·for·ma·tion

noun \ˌprē-fȯr-ˈmā-shən\

Definition of PREFORMATION

: a now discredited theory in biology that every germ cell contains the organism of its kind fully formed and complete in all its parts and that development involves merely an increase in size from microscopic proportions to those of the adult—compare epigenesis

—pre·for·ma·tion·ist \-shə-nəst\ noun or adjective