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]

Moby Thesaurus II by Grady Ward, 1.0:

29 Moby Thesaurus words for "marinate":
   anhydrate, blast-freeze, brine, corn, cure, dehydrate, desiccate,
   dry, dry-cure, dry-salt, embalm, evaporate, freeze, freeze-dry,
   fume, irradiate, jerk, kipper, marinade, mummify, pickle,
   preservatize, quick-freeze, refrigerate, salt, season, smoke,
   smoke-cure, stuff