Protein

Webster's Dictionary of the English Language

·noun A body now known as alkali albumin, but originally considered to be the basis of all albuminous substances, whence its name.

II. Protein ·add. ·noun 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.