[Greek dodeka, twelve.]
A dodecahedron (Greek hedra, seat, base) is a three-dimensional shape having twelve plane faces, while a dodecagon is a plane figure with twelve straight sides and angles. The Dodecanese is a group of twelve islands in the SE Aegean. The term dodecaphonic refers to a system of musical composition, also called the twelve-note or twelve-tone system.
In chemistry, dodecane is the straight chain (aliphatic) hydrocarbon C12H26; dodecyl (see -yl) relates to the radical C12H25—, as in dodecyl aldehyde, also called lauric aldehyde or dodecanal (see -al2), used in perfumery; dodecanoic acid (see -oic), or lauric acid, occurs in many vegetable fats and is used to make soaps and cosmetics.