Quadruple (?), 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]

Quadruple, 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]