n. 1 the flesh of sheep used for food. 2 joc. a sheep. mutton-bird Austral. 1 any bird of the genus Puffinus, esp. the short-tailed shearwater, P. tenuirostris. 2 any of various petrels. mutton chop 1 a piece of mutton, usu. the rib and half vertebra to which it is attached. 2 (in full mutton chop whisker) a side whisker shaped like this. mutton dressed as lamb colloq. a usu. middle-aged or elderly woman dressed or made up to appear younger. mutton-head colloq. a dull, stupid person. mutton-headed colloq. dull, stupid. muttony adj.
[ ME f. OF moton f. med.L multo -onis prob. f. Gaulish ]