Operculum
O`per´cu`lum
| n. | 1. | (Bot.) The lid of a pitcherform leaf. |
| 2. | (Anat.) Any lidlike or operculiform process or part; | |
| 3. | (Zool.) The lid closing the aperture of various species of shells, as the common whelk. See Illust. of Gastropoda. |
| Noun | 1. |  operculum - 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 |