Source : Webster's Revised Unabridged Dictionary (1913)

Triplicate \Trip"li*cate\, a. [L. triplicatus, p. p. of
   triplicare to triple, treble; tri- (see {Tri-}) + plicare to
   fold. See {Ply}, v. t.]
   Made thrice as much; threefold; tripled.

   {Triplicate ratio} (Math.), the ratio of the cubes of two
      quantities; thus, the triplicate ratio of a to b is a^{3}:
      b^{3}.

Triplicate \Trip"li*cate\, n.
   A third thing corresponding to two others of the same kind.

Source : WordNet®

triplicate
     n : one of three copies; any of three things that correspond to
         one another exactly
     v : reproduce threefold; "triplicate the letter for the
         committee"