It means "eatable parts apart from the muscles". It includes the heart, kidneys, lungs, intestines and brains. The word can also be used to cover other parts of the animal including the tongue, tail and feet. The word offal means the parts that fall off when the animal is cut up for meat. Offal from birds are called "giblets". In some parts of the world people eat offal, and in others doing so is considered taboo or strange.