[pree-fawr-mey-shuh n]
  1. previous formation.
  2. Biology. (formerly) the theory that the individual, with all its parts, preexists in the germ cell and grows from microscopic to normal proportions during embryogenesis (opposed to epigenesis).

Origin of preformation

First recorded in 1725–35; pre- + formation
Related formspre·for·ma·tion·ar·y, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for preformation

Historical Examples of preformation

British Dictionary definitions for preformation


  1. the act of forming in advance; previous formation
  2. biology the theory, now discredited, that an individual develops by simple enlargement of a fully differentiated egg cellCompare epigenesis (def. 1)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012