Noun | 1. | ferritin - a protein containing 20% iron that is found in the intestines and liver and spleen; it is one of the chief forms in which iron is stored in the body protein - any of a large group of nitrogenous organic compounds that are essential constituents of living cells; consist of polymers of amino acids; essential in the diet of animals for growth and for repair of tissues; can be obtained from meat and eggs and milk and legumes; "a diet high in protein" |