[计] 四倍

[ noun ]
increase by a factor of four
<noun.process>

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.