Source : Webster's Revised Unabridged Dictionary (1913)

Naphthoquinone \Naph`tho*qui"none\, n. [Naphthalene + quinone.]
   (Chem.)
   A yellow crystalline substance, {C10H6O2}, analogous to
   quinone, obtained by oxidizing naphthalene with chromic acid.

Source : WordNet®

naphthoquinone
     n : a fat-soluble vitamin that helps in the clotting of blood
         [syn: {vitamin K}, {antihemorrhagic factor}]