A saltwater fish that is closely related to but smaller than cod. The lowfat haddock has a firm texture and mild flavor. It can weigh anywhere from 2 to 6 pounds and is available fresh either whole or in fillets and steaks, and frozen in fillets and steaks. Haddock is suitable for any style of preparation including baking, poaching, sautéing and grilling. Smoked haddock is called finnan haddie. See also fish.