The Collaborative International Dictionary of English v.0.48:

Gumbo \Gum"bo\ (g[u^]m"b[-o]), n. [Written also gombo.]
   1. A soup thickened with the mucilaginous pods of the okra;
      okra soup. Especially, A thick stew made with chicken
      (chicken gumbo), or seafood (seafood gumbo), thickened
      with okra or file, and also containing greens and often
      hot spices; it is particularly popular in Louisiana.
      [1913 Webster]

   2. The okra plant or its pods.
      [1913 Webster]

WordNet (r) 3.0 (2006):

gumbo
    n 1: any of various fine-grained silty soils that become waxy
         and very sticky mud when saturated with water [syn:
         gumbo, gumbo soil]
    2: tall coarse annual of Old World tropics widely cultivated in
       southern United States and West Indies for its long
       mucilaginous green pods used as basis for soups and stews;
       sometimes placed in genus Hibiscus [syn: okra, gumbo,
       okra plant, lady's-finger, Abelmoschus esculentus,
       Hibiscus esculentus]
    3: long mucilaginous green pods; may be simmered or sauteed but
       used especially in soups and stews [syn: gumbo, okra]
    4: a soup or stew thickened with okra pods

Moby Thesaurus II by Grady Ward, 1.0:

149 Moby Thesaurus words for "gumbo":
   adhesive, adobe, albumen, amylaceous, batter, bisque, bonnyclabber,
   borscht, bouillabaisse, bouillon, broth, burgoo, butter,
   chicken soup, chowder, clabber, clabbered, clam chowder, clammy,
   clay, clayey, clayish, clear soup, clotted, coagulated, consomme,
   cornstarch, cream, curd, curdled, dough, doughy, earthy,
   egg drop soup, egg white, fish soup, gaum, gaumy, gazpacho, gel,
   gelatin, gelatinous, glair, glairy, glop, glue, gluelike, gluey,
   gluten, glutenous, glutinose, glutinous, goo, gooey, gook, goop,
   gravy soup, gruel, grumous, gumbolike, gumlike, gummous, gummy,
   gunk, heavy, inspissated, jam, jell, jelled, jellied, jelly,
   jellylike, julienne, loamy, loblolly, marly, matzo ball soup,
   minestrone, mire, misoshiru soup, mock turtle soup, molasses,
   mucilage, mucilaginous, muck, mucus, mud, mulligatawny, ooze,
   oxtail soup, pap, paste, pasty, porridge, pot-au-feu, potage,
   potage au tomate, potato soup, pottage, pudding, pulp, puree,
   putty, rob, ropy, semifluid, semiliquid, size, slabby, slime,
   slimy, slip, slithery, slob, slop, slosh, sludge, slush, soily,
   soup, squash, starch, starchy, sticky, sticky mess, stock, stodgy,
   stringy, swill, syrup, syrupy, tacky, tenacious, thick, thick soup,
   thickened, thin soup, tomato soup, tough, treacle, tremelloid,
   tremellose, turtle soup, vegetable soup, vichyssoise, viscid,
   viscose, viscous, won ton soup