Operculum

ō-pėr′kū-lum, n. ( bot. ) a cover or lid: ( zool. ) the plate over the entrance of a shell: the apparatus which protects the gills of fishes:— pl. Oper′cula .— adjs. Oper′cular , belonging to the operculum; Oper′culate , -d , having an operculum; Operculif′erous ; Oper′culiform ; Operculig′enous ; Operculig′erous . [L.,— operīre , to cover.]