n. [ L. quadru- in comp. + E. plane. ] An airplane with four superposed main supporting surfaces. Contrasted with triplane biplane and monoplane. They are now used only for hobbyist or historical activities. [ Webster 1913 Suppl. +PJC ]

a. [ L. quadruplus, from quattuor four: cf. F. quadruple. See Quadrate, and cf. Double. ] Fourfold; as, to make quadruple restitution; a quadruple alliance. [ 1913 Webster ]

Quadruple time (Mus.), that in which each measure is divided into four equal parts. [ 1913 Webster ]

n. [ Cf. F. quadruple, L. quadruplum. ] four times the sum or number; a fourfold amount; as, to receive to quadruple of the amount in damages. [ 1913 Webster ]

v. t. [ imp. & p. p. Quadrupled p. pr. & vb. n. Quadrupling ] [ L. quadruplare: cf. F. quadrupler. ] To multiply by four; to increase fourfold; to double; to double twice. A. Smith. [ 1913 Webster ]

v. i. To be multiplied by four; to increase fourfold; to become four times as much. [ 1913 Webster ]

n. [ From Quadruple. ] 1. A collection or combination of four of a kind. [ Webster 1913 Suppl. ]

2. pl. Four children born in the same labor. [ Webster 1913 Suppl. ]

3. A cycle for carrying four riders, so arranged that all the riders can assist in the propulsion. [ Webster 1913 Suppl. ]

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 ]

v. t. [ imp. & p. p. Quadruplicated p. pr. & vb. n. Quadruplicating. ] [ L. quadruplicatus, p. p. of quadruplicare, fr. quadruple&unr_; fourfold. See Quadruplex. ] To make fourfold; to double twice; to quadruple. [ 1913 Webster ]

a. [ L. quadruplicatus, p. p. ] [ 1913 Webster ]

1. Fourfold; doubled twice; four times repeated; as, a quadruplicate ratio, or a quadruplicate proportion. [ 1913 Webster ]

2. (Math.) Raised to the fourth power. [ R. ] [ 1913 Webster ]

n. [ L. quadruplicatio: cf. F. quadruplication. ] The act of making fourfold; a taking four times the simple sum or amount. [ 1913 Webster ]