The Collaborative International Dictionary of English v.0.48:

Decuple \Dec"u*ple\, a. [F. d['e]cuple, L. decuplus, fr. decem
   ten.]
   Tenfold. [R.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Decuple \Dec"u*ple\, n.
   A number ten times repeated. [R.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Decuple \Dec"u*ple\, v. t. [imp. & p. p. Decupled; p. pr. &
   vb. n. Decupling.]
   To make tenfold; to multiply by ten. [R.]
   [1913 Webster]