Quadruple \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. [1913 Webster]

Source: The Collaborative International Dictionary of English v.0.48
 

Quadruple \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.

Source: Webster's Revised Unabridged Dictionary (1913)