A fish fillet, from the French word filet meaning a thread or strip, is the flesh of a fish which has been cut or sliced away from the bone by cutting lengthwise along one side of the fish parallel to the backbone. In preparation for filleting, any scales on the fish should be removed. The contents of the stomach also need careful detaching from the fillet. Because fish fillets do not contain the larger bones running along the vertebrae, they are often said to be "boneless". However, some species, such as the common carp, have smaller intramuscular bones called pins within the fillet. The skin present on one side may or may not be stripped from the fillet. Butterfly fillets can be produced by cutting the fillets on each side in such a way that they are held together by the flesh and skin of the belly.
Fish fillets can be contrasted with fish steaks (also known as fish cutlets), which are cut perpendicular to the spine and include the larger bones.