"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"@en-us . . . "0"^^ . "0"^^ . "operculum"@en-us . "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"@en-us . "101902368"^^ . . "01902368-n"^^ . "101820994"@en-us . . . . . . . .