The Collaborative International Dictionary of English v.0.48:

Diapente \Di`a*pen"te\ (-p[e^]n"t[-e]), n. [L., fr. Gr.
   dia`pente a fifth; dia` through + pe`nte five: cf. F.
   diapente.]
   1. (Anc. Mus.) The interval of the fifth.
      [1913 Webster]

   2. (Med.) A composition of five ingredients.
      [1913 Webster]