• Webster's Revised Unabridged Dictionary
    • n Protagon (Physiol. Chem) A nitrogenous phosphorized principle found in brain tissue. By decomposition it yields neurine, fatty acids, and other bodies.
    • ***
Century Dictionary and Cyclopedia
    • n protagon A phosphureted, fatty, crystalline substance, which forms a chief constituent of nervous tissue. Its composition has been represented by the formula C160H308N5PO35.
    • n protagon Same as lecithin.
    • ***
Chambers's Twentieth Century Dictionary
    • n Protagon a nitrogenous substance obtained from the brain and other tissues
    • ***


Webster's Revised Unabridged Dictionary
Proto-, + Gr. 'agw`n a contest. See. Protagonist. So called because it was the first definitely ascertained principle of the brain
Chambers's Twentieth Century Dictionary
Gr. prōtos, first, agōnistēs, a combatant.