The Collaborative International Dictionary of English v.0.48:

Tricolor \Tri"col`or\, n. [F. tricolore, drapeau tricolore a
   tricolored flag, fr. tricolore three-colored; tri (see
   Tri-) + L. color color.] [Written also tricolour.]
   [1913 Webster]
   1. The national French banner, of three colors, blue, white,
      and red, adopted at the first revolution.
      [1913 Webster]

   2. Hence, any three-colored flag.
      [1913 Webster]

WordNet (r) 3.0 (2006):

tricolor
    adj 1: having or involving three colors; "trichromatic vision";
           "a trichromatic printing process"; "trichromatic staining
           is the staining of tissue samples differentially in three
           colors"; "tricolor plumage"; "a tricolor process in
           photography" [syn: trichromatic, trichrome,
           tricolor]
    n 1: a flag having three colored stripes (especially the French
         flag) [syn: tricolor, tricolour]

Moby Thesaurus II by Grady Ward, 1.0:

74 Moby Thesaurus words for "tricolor":
   Dannebrog, Jolly Roger, Old Glory, Star-Spangled Banner,
   Stars and Stripes, Union Flag, Union Jack, and blue, banderole,
   banner, banneret, bicolor, bicolored, black flag, blue ensign,
   bunting, burgee, coachwhip, colorful, colors, colory, crazy,
   daedal, dichromatic, divers-colored, ensign, flag, gonfalon,
   gonfanon, guidon, harlequin, house flag, jack, kaleidoscopic,
   long pennant, many-colored, medley, merchant flag, motley,
   multicolor, multicolored, multicolorous, national flag, oriflamme,
   parti-color, parti-colored, pennant, pennon, pennoncel,
   polychromatic, polychrome, polychromic, prismal, red, red ensign,
   royal standard, shot, shot through, signal flag, spectral,
   standard, streamer, swallowtail, thunder and lightning,
   trichromatic, trichromic, tricolored, two-tone, varicolored,
   variegated, versicolor, versicolored, vexillum, white