Hyper Dictionary

English Dictionary Computer Dictionary Video Dictionary Thesaurus Dream Dictionary Medical Dictionary

Search Dictionary:  

Meaning of OPERCULUM

Pronunciation:  ow'purkyulum

WordNet Dictionary
[n]  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

OPERCULUM is a 9 letter word that starts with O.


 See Also: plate



Webster's 1913 Dictionary
\O*per"cu*lum\, n.; pl. L. {Opercula}, E.
{Operculums}. [L., a cover or lid, fr. operire to cover.]
1. (Bot.)
   (a) The lid of a pitcherform leaf.
   (b) The lid of the urnlike capsule of mosses.

2. (Anat.)
   (a) Any lidlike or operculiform process or part; as, the
       opercula of a dental follicle.
   (b) The fold of integument, usually supported by bony
       plates, which protects the gills of most fishes and
       some amphibians; the gill cover; the gill lid.
   (c) The principal opercular bone in the upper and
       posterior part of the gill cover.

3. (Zo["o]l.)
   (a) The lid closing the aperture of various species of
       shells, as the common whelk. See Illust. of
   (b) Any lid-shaped structure closing the aperture of a
       tube or shell.

Biology Dictionary
  1. In mosses, a cap-like structure covering or partly covering the capsule and derived from the neck of the archegonium; in a flower, a cap covering the stamens and carpels in the bud and formed by fusion or cohesion of perianth parts.
  2. A lid or cover becoming detached at maturity by abscission; in Eucalyptus (for example), a cap covering the bud and formed by fusion or cohesion of perianth parts.