What is "operculums"

Operculum \O*per"cu*lum\, n.; pl. L. Opercula, E. Operculums. [L., a cover or lid, fr. operire to cover.]

1. (Bot.)

   1. The lid of a pitcherform leaf.

   2. The lid of the urnlike capsule of mosses.

2. (Anat.)

   1. Any lidlike or operculiform process or part; as, the opercula of a dental follicle.

   2. 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.

   3. The principal opercular bone in the upper and posterior part of the gill cover.

3. (Zo["o]l.)

   1. The lid closing the aperture of various species of shells, as the common whelk. See Illust. of Gastropoda.

   2. Any lid-shaped structure closing the aperture of a tube or shell.