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preformation

[pree-fawr-mey-shuh n]
noun
  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).
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Origin of preformation

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

Examples from the Web for preformation

Historical Examples

  • Preformation, identical with the original meaning of evolution, which see.

    The Biological Problem of To-day

    Oscar Hertwig

  • Preformation: the doctrine of growth or development from already existing rudiments; opposed to epigenesis: q.v.

  • Let us first cast a historical glance at the older ontogeny, and the theory of preformation which is connected with it.

  • In this respect it is like its predecessor, the theory of preformation of the eighteenth century.

  • His shrewd comment on the preformation notion of development has been quoted (p. 20).


British Dictionary definitions for preformation

preformation

noun
  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)
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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