The Collaborative International Dictionary of English v.0.48:

colors \colors\ n.
   1. a flag flown by a ship to show its nationality.

   Syn: ensign, colours.
        [WordNet 1.5]

   2. a distinguishing emblem; as, his tie proclaimed his school
      colors.

   Syn: colours.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

colors
    n 1: a flag that shows its nationality [syn: colors,
         colours]
    2: a distinguishing emblem; "his tie proclaimed his school
       colors" [syn: colors, colours]

Moby Thesaurus II by Grady Ward, 1.0:

77 Moby Thesaurus words for "colors":
   Communist threat, Dannebrog, Jolly Roger, Old Glory,
   Star-Spangled Banner, Stars and Stripes, Union Flag, Union Jack,
   Western imperialism, adornment, and blue, atrocity story,
   banderole, banner, banneret, battle hymn, beauties, black flag,
   bloody shirt, blue ensign, bunting, burgee, coachwhip,
   colors of rhetoric, crostarie, elegant variation, embellishment,
   embroidery, ensign, expansionism, face, fiery cross, figure,
   figure of speech, fine writing, flag, floridity, floridness,
   flourish, floweriness, flowers of speech, frill, gonfalon,
   gonfanon, guidon, house flag, imperialist threat, independence,
   jack, long pennant, lushness, luxuriance, manifest destiny,
   martial music, merchant flag, national anthem, national flag,
   oriflamme, ornament, ornamentation, pennant, pennon, pennoncel,
   purple patches, red, red ensign, royal standard,
   self-determination, signal flag, standard, streamer, swallowtail,
   tricolor, vexillum, war song, white, yellow peril