animalculist /anɪˈmalkjʊlɪst/noun 2adjective 1forms 3 noun2 •(historical) A believer in the theory that the embryo exists preformed within the spermatozoon; a proponent of animalculism. •(no longer used) Someone who studies animalcules. adjective1 •(historical) Pertaining to animalculism.Countering ‘ovism’, the rival ‘animalculist’ school regarded spermatozoa, discovered in semen by Leeuwenhoek, as the true source of conception. — 1997 formsanimalculists · more animalculist · most animalculist