Source : Webster's Revised Unabridged Dictionary (1913)

Ingrain \In"grain`\ (?; 277), a. [Pref. in- in + grain kermes.
   See {Engrain}, {Grain}.]
   1. Dyed with grain, or kermes. [Obs.]

   2. Dyed before manufacture, -- said of the material of a
      textile fabric; hence, in general, thoroughly inwrought;
      forming an essential part of the substance.

   {Ingrain carpet}, a double or two-ply carpet.

   {Triple ingrain carpet}, a three-ply carpet.