资料来源 : Webster's Revised Unabridged Dictionary (1913)

Duplicate \Du"pli*cate\, a. [L. duplicatus, p. p. of duplicare
   to double, fr. duplex double, twofold. See {Duplex}.]
   Double; twofold.

   {Duplicate proportion} or {ratio} (Math.), the proportion or
      ratio of squares. Thus, in geometrical proportion, the
      first term to the third is said to be in a duplicate ratio
      of the first to the second, or as its square is to the
      square of the second. Thus, in 2, 4, 8, 16, the ratio of 2
      to 8 is a duplicate of that of 2 to 4, or as the square of
      2 is to the square of 4.