Operculum - Definitions from Dictionary.com

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Dictionary.com Unabridged (v 1.1) - Cite This Source - Share This

o·per·cu·lum

Audio Help [oh-pur-kyuh-luh

m] Pronunciation Key

–noun, plural -la

Audio Help [-luh] Pronunciation Key, -lums.

1.	Botany, Zoology. a part or organ serving as a lid or cover, as a covering flap on a seed vessel.

Zoology.

a.	the gill cover of fishes and amphibians.

b.	(in many gastropods) a horny plate that closes the opening of the shell when the animal is retracted.

[Origin: 1705–15; < NL, L: lid, cover, equiv. to oper(īre) to cover + -culum -cule²

]

—Related forms

o·per·cu·lar, adjective

Dictionary.com Unabridged (v 1.1)
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2006.

Encyclopædia Britannica, Inc.
Operculum

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American Heritage Dictionary - Cite This Source - Share This

o·per·cu·lum Audio Help (ō-pûr'kyə-ləm) Pronunciation Key
n. pl. o·per·cu·la (-lə) or o·per·cu·lums
A lid or flap covering an aperture, such as the gill cover in some fishes or the horny shell cover in snails or other mollusks.

[Latin, lid, from operīre, to cover; see wer-⁴ in Indo-European roots.]

o·per'cu·lar (-lər) adj., o·per'cu·lar·ly adv.

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The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2006 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.

WordNet - Cite This Source - Share This

operculum
noun
a hard flap serving as a cover for (a) the gill slits in fishes or (b) the opening of the shell in certain gastropods when the body is retracted

The American Heritage Science Dictionary - Cite This Source - Share This

operculum Audio Help (ō-pûr'kyə-ləm) Pronunciation Key
Plural opercula or operculums
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 © 2002 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.

American Heritage Stedman's Medical Dictionary - Cite This Source - Share This

operculum o·per·cu·lum (ō-pûr'kyə-ləm)
n. pl. o·per·cu·lums or o·per·cu·la (-lə)

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.

o·per'cu·lar (-lər) adj.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Merriam-Webster's Medical Dictionary - Cite This Source - Share This
Main Entry: oper·cu·lum
Pronunciation: O-'p&r-ky&-l&m
Function: noun
Inflected Form: plural oper·cu·la /-l&/ also oper·cu·lums
: any of several parts of the cerebrum bordering the sylvian fissure and concealing the insula

Webster's Revised Unabridged Dictionary - Cite This Source - Share This

Operculum

Gill\, n. [Dan. gi[ae]lle, gelle; akin to Sw. g["a]l, Icel. gj["o]lnar gills; cf. AS. geagl, geahl, jaw.]

1. (Anat.) An organ for aquatic respiration; a branchia.

Fishes perform respiration under water by the gills. --Ray.

Note: Gills are usually lamellar or filamentous appendages, through which the blood circulates, and in which it is exposed to the action of the air contained in the water. In vertebrates they are appendages of the visceral arches on either side of the neck. In invertebrates they occupy various situations.

2. pl. (Bot.) The radiating, gill-shaped plates forming the under surface of a mushroom.

3. (Zo["o]l.) The fleshy flap that hangs below the beak of a fowl; a wattle.

4. The flesh under or about the chin. --Swift.

5. (Spinning) One of the combs of closely ranged steel pins which divide the ribbons of flax fiber or wool into fewer parallel filaments. [Prob. so called from F. aiguilles, needles. --Ure.]

Gill arches, Gill bars. (Anat.) Same as Branchial arches.

Gill clefts. (Anat.) Same as Branchial clefts. See under Branchial.

Gill cover, Gill lid. See Operculum.

Gill frame, or Gill head (Flax Manuf.), a spreader; a machine for subjecting flax to the action of gills. --Knight.

Gill net, a flat net so suspended in the water that its meshes allow the heads of fish to pass, but catch in the gills when they seek to extricate themselves.

Gill opening, or Gill slit (Anat.), an opening behind and below the head of most fishes, and some amphibians, by which the water from the gills is discharged. In most fishes there is a single opening on each side, but in the sharks and rays there are five, or more, on each side.

Gill rakes, or Gill rakers (Anat.), horny filaments, or progresses, on the inside of the branchial arches of fishes, which help to prevent solid substances from being carried into gill cavities.

On-line Medical Dictionary - Cite This Source - Share This

operculum

operculum: in CancerWEB's On-line Medical Dictionary

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