資料來源 : Webster's Revised Unabridged Dictionary (1913)

Penta- \Pen"ta-\ [Gr. ?, a later combining form of ? five. See
   {Five}.]
   1. A combining form denoting five; as, pentacapsular;
      pentagon.

   2. (Chem.) Denoting the degree of five, either as regards
      quality, property, or composition; as, pentasulphide;
      pentoxide, etc. Also used adjectively.