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

Subduple \Sub"du*ple\, a. (Math.)
   Indicating one part of two; in the ratio of one to two.

   {Subduple ratio}, the ratio of 1 to 2: thus, 3:6 is a
      subduple ratio, as 6:3 is a duple ratio.