- 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 opercular
The Opercular Valves are large, owing to the form of the shell.
The al are added to above the level of the opercular membrane.
They are joined to the sheath of the shell by the opercular membrane.
The opercular has a facet for articulation with the hyomandibular.The Vertebrate Skeleton
Sidney H. Reynolds
The opercular valves, or pieces placed so as to enclose the aperture.A Conchological Manual
George Brettingham Sowerby
- 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- the bony plate in certain gastropods covering the opening of the shell when the body is withdrawn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 opercular
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.