The Collaborative International Dictionary of English v.0.48:

Bechamel \Bech"a*mel\, n. [F. b['e]chamel, named from its
   inventor, Louis de B['e]chamel.] (Cookery)
   A rich, white sauce, prepared with butter and cream.
   [1913 Webster]

WordNet (r) 3.0 (2006):

bechamel
    n 1: milk thickened with a butter and flour roux [syn: white
         sauce, bechamel sauce, bechamel]