Bone is the rigid skeleton of most veterbrate animals. It is encountered in cooking either as part of a cut of meat, typically called "bone-in," or is used directly. Bones can be cooked in boiling liquid to extract gelatine, which is used to smooth and thicken stocks, and they can be roasted with dry heat to improve flavor.
Bone marrow, the soft fatty center of the long bones of some mammals, especially beef and veal, is prepared to be eaten as a dish, or is included in sauces and fillings.