Quad"ru*ple (?), a. [L. quadruplus, from quattuor four: cf. F. quadruple. See Quadrate, and cf. Double.] Fourfold; as, to make quadruple restitution; a quadruple alliance.

Quad"ru*ple, 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.

Quad"ru*ple, 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.

Quad"ru*ple, v. i. To be multiplied by four; to increase fourfold; to become four times as much.

• being four times as long, as big or as many of something.
       He's quite an athlete and can do quadruple jumps with ease.
  
• to multiply something by four times.
       Our profits quadrupled when we made the improvements.