• synonyms


  1. Zoology. any minute opening in an ovum through which a spermatozoon can enter, as in many insects.
  2. Botany. the minute orifice or opening in the integuments of an ovule.
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Origin of micropyle

1815–25; micro- + Greek pýlē gate
Related formsmi·cro·py·lar, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for micropyle

Historical Examples

  • The micropyle covers the upper surface of the egg and is not depressed.

    The Butterfly Book

    William Jacob Holland

  • Micropyle, answering to the Foramen or orifice of the ovule.

  • Every ovule has a tiny opening, or micropyle as it is called, and it is now easy to guess what that is for.

  • At one end a cap-like portion of this forms a detachable operculum, in the middle of which is a minute opening, the micropyle.

  • In some cases it is advisable to slice off the end of the egg with the micropyle and mount it microscopically.

British Dictionary definitions for micropyle


  1. a small opening in the integuments of a plant ovule through which the male gametes pass
  2. a small pore in the shell of an insect's eggs through which the sperm passes
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Derived Formsmicropylar, adjective

Word Origin

C19: from micro- + Greek pulē gate
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

micropyle in Science


  1. A minute opening in the ovule of a seed plant through which the pollen tube usually enters.
  2. A pore in the membrane covering the ovum of some animals through which a spermatozoon can enter.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.