The Collaborative International Dictionary of English v.0.48:

Chestnut \Chest"nut\, n. [For chesten-nut; OE. chestein,
   chesten, chastein, chestnut, fr. AS. cisten in cistenbe['a]m
   chestnut tree, influenced by OF. chastaigne, F. ch[^a]taigne,
   both the AS. and the F. words coming from L. castanea a
   chestnut, Gr. ?, fr. ? a city of Pontus, where chestnut trees
   grew in abundance, and whence they were introduced into
   Europe. Cf. Castanets.]
   1. (Bot.) The edible nut of a forest tree (Castanea vesce)
      of Europe and America. Commonly two or more of the nuts
      grow in a prickly bur.
      [1913 Webster]

   2. The tree itself, or its light, coarse-grained timber, used
      for ornamental work, furniture, etc.
      [1913 Webster]

   3. A bright brown color, like that of the nut.
      [1913 Webster]

   4. The horse chestnut (often so used in England).
      [1913 Webster]

   5. One of the round, or oval, horny plates on the inner sides
      of the legs of the horse, and allied animals.
      [1913 Webster]

   6. An old joke or story. [Slang]
      [1913 Webster]

   Chestnut tree, a tree that bears chestnuts.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Chestnut \Chest"nut\, a.
   Of or pertaining of a chestnut; of a reddish brown color; as,
   chestnut curls.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

colorful \colorful\ adj.
   1. having striking color. Opposite of colorless.

   Note: [Narrower terms: changeable, chatoyant, iridescent,
         shot; deep, rich; flaming; fluorescent, glowing;
         prismatic; psychedelic; red, ruddy, flushed,
         empurpled]

   Syn: colourful.
        [WordNet 1.5]

   2. striking in variety and interest. Opposite of colorless
      or dull. [Narrower terms: brave, fine, gay, glorious;
      flamboyant, resplendent, unrestrained; flashy, gaudy,
      jazzy, showy, snazzy, sporty; picturesque]
      [WordNet 1.5]

   3. having color or a certain color; not black, white or grey;
      as, colored crepe paper. Opposite of colorless and
      monochrome.

   Note: [Narrower terms: tinted; touched, tinged; amber,
         brownish-yellow, yellow-brown; amethyst; auburn,
         reddish-brown; aureate, gilded, gilt, gold, golden;
         azure, cerulean, sky-blue, bright blue; bicolor,
         bicolour, bicolored, bicoloured, bichrome; blue,
         bluish, light-blue, dark-blue; blushful,
         blush-colored, rosy; bottle-green; bronze, bronzy;
         brown, brownish, dark-brown; buff; canary,
         canary-yellow; caramel, caramel brown; carnation;
         chartreuse; chestnut; dun; earth-colored,
         earthlike; fuscous; green, greenish, light-green,
         dark-green; jade, jade-green; khaki; lavender,
         lilac; mauve; moss green, mosstone; motley,
         multicolor, culticolour, multicolored, multicoloured,
         painted, particolored, particoloured, piebald, pied,
         varicolored, varicoloured; mousy, mouse-colored;
         ocher, ochre; olive-brown; olive-drab; olive;
         orange, orangish; peacock-blue; pink, pinkish;
         purple, violet, purplish; red, blood-red, carmine,
         cerise, cherry, cherry-red, crimson, ruby, ruby-red,
         scarlet; red, reddish; rose, roseate; rose-red;
         rust, rusty, rust-colored; snuff, snuff-brown,
         snuff-color, snuff-colour, snuff-colored,
         snuff-coloured, mummy-brown, chukker-brown; sorrel,
         brownish-orange; stone, stone-gray; straw-color,
         straw-colored, straw-coloured; tan; tangerine;
         tawny; ultramarine; umber; vermilion,
         vermillion, cinibar, Chinese-red; yellow, yellowish;
         yellow-green; avocado; bay; beige; blae
         bluish-black or gray-blue); coral; creamy; cress
         green, cresson, watercress; hazel; honey,
         honey-colored; hued(postnominal); magenta;
         maroon; pea-green; russet; sage, sage-green;
         sea-green] [Also See: chromatic, colored, dark,
         light.]

   Syn: colored, coloured, in color(predicate).
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

chestnut
    adj 1: (of hair or feathers) of a golden brown to reddish brown
           color; "a chestnut horse"; "chestnut hair"
    n 1: wood of any of various chestnut trees of the genus Castanea
    2: any of several attractive deciduous trees yellow-brown in
       autumn; yield a hard wood and edible nuts in a prickly bur
       [syn: chestnut, chestnut tree]
    3: edible nut of any of various chestnut trees of the genus
       Castanea
    4: the brown color of chestnuts
    5: a small horny callus on the inner surface of a horse's leg
    6: a dark golden-brown or reddish-brown horse

Moby Thesaurus II by Grady Ward, 1.0:

84 Moby Thesaurus words for "chestnut":
   Joe Miller, Titian, adust, auburn, banality, bay, bay-colored,
   bayard, brazen, bromide, bronze, bronze-colored, bronzed,
   brownish-red, buckskin, calico pony, carroty, castaneous,
   chestnut-brown, cliche, commonplace, commonplace expression,
   copper, copper-colored, coppery, corn, cupreous, dapple-gray, dun,
   erythristic, familiar tune, ferruginous, foxy, gray, grizzle,
   hackneyed saying, henna, joke with whiskers, lieu commun,
   liver-brown, liver-colored, livid-brown, locus communis, mahogany,
   old joke, old saw, old song, old story, old turkey, old wheeze,
   paint, painted pony, piebald, pinto, platitude, prosaicism,
   prosaism, prose, red-crested, red-haired, red-polled, red-tufted,
   reddish-brown, reiteration, retold story, roan, rubiginous, rufous,
   russet, russety, rust, rust-colored, rusty, skewbald, sorrel,
   stereotyped saying, sunburned, terra-cotta, trite joke,
   trite saying, triticism, twice-told tale, warmed-over cabbage,
   xanthous