a. [ L., from quattuor four + plicare to fold. ] Fourfold; folded or doubled twice. [ 1913 Webster ]
Quadruplex system (Electric Telegraph), a system by which four messages, two in each direction, may be sent simultaneously over the wire. [ 1913 Webster ]
(adj) having four units or components, Syn. fourfold, four-fold, quadruplex, quadruplicate, Example:quadruple rhythm has four beats per measure; quadruplex wire