預先形成
Preformation \Pre`for*ma"tion\, n. (Biol.) An old theory of the pre["e]xistence of germs. Cf. {Embo[^i]tement}.
preformation n : a theory (popular in the 18th century and now discredited) that an individual develops by simple enlargement of a tiny fully formed organism (a homunculus) that exists in the germ cell [syn: {theory of preformation}]