- Botany, Zoology. a part or organ serving as a lid or cover, as a covering flap on a seed vessel.
- the gill cover of fishes and amphibians.
- (in many gastropods) a horny plate that closes the opening of the shell when the animal is retracted.
Origin of operculum
1705–15; < New Latin, Latin: lid, cover, equivalent to oper(īre) to cover + -culum -cule2
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for operculum
The operculum fits the entrance to its shell like a trap door.Japanese Fairy World
William Elliot Griffis
Sometimes, however, its form is conical or spiral, with or without an operculum.
The outer lip is also thickened and bent inward, and there is no operculum.
In Cryptohelia the cyclosystem is covered by a cap or operculum.
This flap, an outgrowth of the hyoid arch, is known as the operculum.
- the hard bony flap covering the gill slits in fishes
- the bony plate in certain gastropods covering the opening of the shell when the body is withdrawn
- botany the covering of the spore-bearing capsule of a moss
- biology any other covering or lid in various organisms
C18: via New Latin from Latin: lid, from operīre to cover
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
Word Origin and History for operculum
1713, from Latin operculum "cover, lid," from operire "to cover, close" (see weir), with instrumental suffix *-tlom. Related: Opercular.
Online Etymology Dictionary, © 2010 Douglas Harper
- Something resembling a lid or cover.
- The portions of the frontal, parietal, and temporal lobes covering the insula.
- The mucus sealing the endocervical canal of the uterus after conception.
- The attached flap in cases of torn retinal detachment.
- The mucosal flap partially or completely covering an unerupted tooth.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
- A lid or flap covering an opening, such as the gill cover in some fish or the horny flap covering the opening of a snail.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.