quadruplex

Adjective

quad=ru=plex

WORDNET DICTIONARY

quadruplex(s = adj.all) four-fold, fourfold, quadruple, quadruplicate - having four units or components; "quadruple rhythm has four beats per measure"; "quadruplex wire"

quadruplex, 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.