a. [ L. quadruplus, from quattuor four: cf. F. quadruple. See Quadrate, and cf. Double. ] Fourfold;
Quadruple time (Mus.),
n. [ Cf. F. quadruple, L. quadruplum. ] four times the sum or number; a fourfold amount;
v. t.
v. i. To be multiplied by four; to increase fourfold; to become four times as much. [ 1913 Webster ]
n. [ From Quadruple. ]
a. [ L., from quattuor four + plicare to fold. ] Fourfold; folded or doubled twice. [ 1913 Webster ]
Quadruplex system (Electric Telegraph),