Source : Webster's Revised Unabridged Dictionary (1913)

Two-ply \Two"-ply`\, a.
   1. Consisting of two thicknesses, as cloth; double.

   2. Woven double, as cloth or carpeting, by incorporating two
      sets of warp thread and two of weft.

Source : WordNet®

two-ply
     adj : having a thickness made up of two layers or strands