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Related to preformation: Preformation theory


1. The act of shaping or forming in advance; prior formation.
2. A theory popular in the 1700s that all parts of an organism exist completely formed in the germ cell and develop only by increasing in size.


1. the act of forming in advance; previous formation
2. (Biology) biology the theory, now discredited, that an individual develops by simple enlargement of a fully differentiated egg cell. Compare epigenesis1


(ˌpri fɔrˈmeɪ ʃən)

1. previous formation.
2. a former biological theory that the individual preexists fully formed in the germ cell and grows from microscopic to normal proportions during the embryo phase.


the theory that germ cells contain every part of the future organism in miniature form, future development being only a matter of increase in size. Cf. epigenesis.
See also: Biology
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.preformation - a theory (popular in the 18th century and now discredited) that an individual develops by simple enlargement of a tiny fully formed organism (a homunculus) that exists in the germ cell
theory - a well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena; "theories can incorporate facts and laws and tested hypotheses"; "true in fact and theory"
References in periodicals archive ?
Preformation of IVF on women with endometriosis may be a potential risk factor for SHiP.
Mahmoud Mirbagheri said the boost was made possible after completion of 25 acidizing, cementing and preformation operations over the wells operated by the company during the current Iranian calendar year which began on March 21.
In this crosslinking system, ethanol is present to block or hinder the reaction between the carbamylated resin and the CHDA, through the preformation of acet als.
Women with Cu-T other than 380A who refused to give consent for participation, women with failure or suspected preformation and women with newly-diagnosed medical or gynaecological disease were excluded from the study.
I wondered, lastly, how this study's concrete interest in the German business of translation might relate to its distinctive intellectual preformation from Herder, say, to Schleiermacher and the Schlegels: a tradition in which German features as the single most cross-culturally evolved, and hence authentically foreignizing, of the European languages, and German writers therefore as a band of cosmopolitans-in-chief.
At unary twist and backtwist and a preformation are designed to provide lack of torsion and bend deformation of wires [1 .
Consequences of preformation for dynamic resource allocation by a carnivorous herb, Pinguicula vulgaris (Lentibulariaceae).
The preformation of our method in the process time is medium compared with other methods.
In this study, we instead adopt a storm-centered area-averaging approach over a 2[degrees] radius in order to obtain a representative SST on the storm scale without introducing a potential bias from storms with short preformation tracks.
Extavour CG, Akam M (2003) Mechanisms of germ cell specification across the metazoans: epigenesis and preformation.
The proposed rules also change the treatment of preformation capital expenditures under Regs.
Another existing exception to the disguised-sale rules is for reimbursements of preformation expenditures (Regs.