Definition of preformation in English:



  • 1The action or process of preforming something.

    • ‘The organogenetic event which initiated the neoformed organs continued until early autumn, giving rise to the following year's preformation.’
    • ‘The classification also encompasses physiological processes that are underlying phenomena of preformation and neoformation.’
    • ‘If ‘seeing is believing,’ most still wanted to believe in preformation, and so they convinced themselves that they saw little men and tiny animals when they peered into their microscopes.’
    • ‘Moreover, information concerning both the co-occurrence of preformation and neoformation within the same shoot system is virtually non-existent.’
    1. 1.1Biology historical The theory, now discarded, that an embryo develops from a complete miniature version of the organism.
      Often contrasted with epigenesis
      • ‘Each in turn examined the theory of preformation in the light of natural philosophy and religion.’
      • ‘Development could not therefore be based on preformation but must be epigenetic, because during development many new cells are generated by division from the egg, and new types of cell are formed.’
      • ‘Accordingly, near the turn of this century, many biologists who espoused or contested theories of evolution, meant, among other things, to support or undermine theories of the preformation of species according to a developmental plan.’