• synonyms


[proh-noo-klee-uh s, -nyoo-]
noun, plural pro·nu·cle·i [proh-noo-klee-ahy, -nyoo-] /proʊˈnu kliˌaɪ, -ˈnyu-/. Cell Biology.
  1. either of the gametic nuclei that unite in fertilization to form the nucleus of the zygote.
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Origin of pronucleus

From New Latin, dating back to 1875–80; see origin at pro-1, nucleus
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for pronucleus


noun plural -clei (-klɪˌaɪ)
  1. the nucleus of a mature ovum or spermatozoan before fertilization
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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

pronucleus in Medicine


  1. One of two nuclei undergoing fusion in karyogamy.
  2. The haploid nucleus of a sperm or egg before fusion of the nuclei in fertilization.
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The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.