The Collaborative International Dictionary of English v.0.48:

Chowder \Chow"der\ (chou"d[~e]r), n. [F. chaudi[`e]re a kettle,
   a pot. Cf. Caldron.]
   1. (Cookery) A dish made of fresh fish or clams, biscuit,
      onions, etc., stewed together.
      [1913 Webster]

   2. A seller of fish. [Prov. Eng.] --Halliwell.
      [1913 Webster]

   Chowder beer, a liquor made by boiling black spruce in
      water and mixing molasses with the decoction.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Chowder \Chow"der\, v. t.
   To make a chowder of.
   [1913 Webster]

WordNet (r) 3.0 (2006):

chowder
    n 1: a thick soup or stew made with milk and bacon and onions
         and potatoes

Moby Thesaurus II by Grady Ward, 1.0:

52 Moby Thesaurus words for "chowder":
   Irish stew, bisque, borscht, bouillabaisse, bouillon, broth,
   burgoo, chicken soup, clam chowder, clear soup, consomme, curry,
   egg drop soup, etuvee, fish soup, fricassee, gazpacho, goulash,
   gravy soup, gumbo, julienne, matzo ball soup, meat stew,
   minestrone, misoshiru soup, mock turtle soup, mulligan,
   mulligan stew, mulligatawny, olio, olla, olla podrida, oxtail soup,
   oyster stew, paella, pot-au-feu, potage, potage au tomate,
   potato soup, pottage, puree, ragout, soup, stew, stock, thick soup,
   thin soup, tomato soup, turtle soup, vegetable soup, vichyssoise,
   won ton soup