Protein /(?)/

Pro·te·in

Protein

n.
  1. In chemical analysis, the total nitrogenous material in vegetable or animal substances, obtained by multiplying the total nitrogen found by a factor, usually 6.25, assuming most proteids to contain approximately 16 per cent of nitrogen. (Physiol. Chem.)

Protein

n.
  1. A body now known as alkali albumin, but originally considered to be the basis of all albuminous substances, whence its name. (Physiol. Chem.) [Outdated]
  2. Any of numerous large, complex naturally-produced molecules composed of one or more long chains of amino acids. (Biochem.)
  3. One of three major classes of food or source of food energy (4 kcal/gram), abundant in animal-derived foods (i.e. meat) and some vegetables, such as legumes. (Nutrition)

Phrases & Compounds
Protein crystal
See Crystalloid, n., 2.