n. 1 either of a pair of similar things, esp. either of two words of the same derivation but different sense (e.g. fashion and faction, cloak and clock). 2 hist. a man's short close-fitting jacket, with or without sleeves. 3 a historical or biblical account occurring twice in differing contexts, usu. traceable to different sources. 4 (in pl.) the same number on two dice thrown at once. 5 a pair of associated lines close together in a spectrum. 6 a combination of two simple lenses.
[ ME f. OF f. double: see DOUBLE ]