Noun, pl. opercula
1. A covering flap or lidlike structure in plants and animals, such as a gill cover. (wiktionary.org)
2. (Brain), the part of the brain covering the insula.
3. (Dentistry), a small flap of tissue which may cover an erupting or partially erupted molar.
1. (Animal), a structure resembling a lid or a small door that opens and closes.
2. (Fish), a flap of the bony fish covering the gills.
3. (Gastropod), a lid on the shell of some gastropods.
4. (Bird), a structure which covers the nares of some birds.
5. (Bryozoa), a lid on the orifice of some bryozoans.
6. The anterior end of the fruit fly puparium, through which the adult fly emerges.
1. Various lids and flaps pertaining to plants, algae and fungi.
Word origin: From Latin operculum “cover, lid,” from operire “to cover, close.”