The Collaborative International Dictionary of English v.0.48:

Broth \Broth\, n. [AS. bro[eth]; akin to OHG. brod, brot; cf.
   Ir. broth, Gael. brot. [root]93. Cf. Brewis, Brew.]
   Liquid in which flesh (and sometimes other substances, as
   barley or rice) has been boiled; thin or simple soup.
   [1913 Webster]

         I am sure by your unprejudiced discourses that you love
         broth better than soup.                  --Addison.
   [1913 Webster]

WordNet (r) 3.0 (2006):

broth
    n 1: liquid in which meat and vegetables are simmered; used as a
         basis for e.g. soups or sauces; "she made gravy with a base
         of beef stock" [syn: broth, stock]
    2: a thin soup of meat or fish or vegetable stock

Moby Thesaurus II by Grady Ward, 1.0:

38 Moby Thesaurus words for "broth":
   bisque, borscht, bouillabaisse, bouillon, burgoo, chicken soup,
   chowder, clam chowder, clear soup, consomme, decoction,
   egg drop soup, fish soup, gazpacho, gravy soup, gumbo, julienne,
   matzo ball soup, minestrone, misoshiru soup, mock turtle soup,
   mulligatawny, oxtail soup, pot-au-feu, potage, potage au tomate,
   potato soup, pottage, puree, soup, stock, thick soup, thin soup,
   tomato soup, turtle soup, vegetable soup, vichyssoise,
   won ton soup