noun ·Rare ·Advanced level

Definitions

Noun

1. 1
   the theory that all organisms start their existence already in a predetermined form upon conception and this form does not change in the course of their lifetime (as opposed to epigenesis) uncountable

Etymology

From preformation + -ism.

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.