The Collaborative International Dictionary of English v.0.48:

Marinate \Mar"i*nate\, v. t. [See Marine, and cf. Marinade.]
   To salt or pickle, as fish, and then preserve in oil or
   vinegar; to prepare (food) by the use of marinade.
   [1913 Webster]

WordNet (r) 3.0 (2006):

marinate
    v 1: soak in marinade; "marinade herring" [syn: marinade,
         marinate]