A marinade is the wet mix you put meat, fish, or sometimes vegetables into before you cook them. People usually make it with oil, plus something sour (lemon, vinegar, wine), and salt, garlic, herbs, or soy sauce — whatever will give the food more taste. You leave the food sitting in it for a while so the outside picks up flavour; though actually it does not soak all the way through a thick piece of meat the way cookbooks sometimes make it sound. In American English, marinade is almost always the mix itself (a noun), and the action is marinate. In British English, some people also use marinade as a verb: they marinade the chicken overnight. Both are understood. It is ordinary kitchen talk, not a fancy word. Cooks stretch it a little (a yoghurt marinade, even a “dry marinade” of spices with almost no liquid), though a truly dry rub is not really a marinade.