Definition of preformation
preformationistplay \-sh(ə-)nist\ noun or adjective
First Known Use of preformation
Medical Definition of preformation
: a now discredited theory in biology that every germ cell contains the organism of its kind fully formed and complete in all its parts and that development involves merely an increase in size from microscopic proportions to those of the adult—compare epigenesis
preformationist\-shə-nəst\play noun or adjective
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