The Collaborative International Dictionary of English v.0.48:

Duplicate \Du"pli*cate\, v. t. [imp. & p. p. Duplicated; p.
   pr. & vb. n. Duplicating.]
   1. To double; to fold; to render double.
      [1913 Webster]

   2. To make a duplicate of (something); to make a copy or
      transcript of. --Glanvill.
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   3. (Biol.) To divide into two by natural growth or
      spontaneous action; as, infusoria duplicate themselves.
      [1913 Webster]