a particular complex anatomical part of a living thing and its construction and arrangement

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

ciliated comb-like swimming plate of a ctenophore

(paleontology) a bony plate that curves upward behind the skull of many ceratopsian dinosaurs

a thin plate or layer (especially of bone or mineral)