PROTEIN

noun Usage: often attributive see: prot- Date: circa 1844 any of various naturally occurring extremely complex substances that consist of amino-acid residues joined by peptide bonds, contain the elements carbon, hydrogen, nitrogen, oxygen, usually sulfur, and occasionally other elements (as phosphorus or iron), and include many essential biological compounds (as enzymes, hormones, or antibodies), the total nitrogenous material in plant or animal substances