noun, plural o·per·cu·la [oh-pur-kyuh-luh] /oʊˈpɜr kyə lə/, o·per·cu·lums.
- 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
Examples from the Web for operculum
Historical Examples of 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.
noun plural -la (-lə) or -lums
- 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- the bony plate in certain gastropods covering the opening of the shell when the body is withdrawn
Word Origin for operculum
1713, from Latin operculum "cover, lid," from operire "to cover, close" (see weir), with instrumental suffix *-tlom. Related: Opercular.