vitamin k3(n = noun.substance) menadione - a form of vitamin K;
is a kind of antihemorrhagic factor, naphthoquinone, vitamin k

   menadione, (C11H8O2) being chemically 2-methyl-1,4,-naphthoquinone. Having no side chain in the 3 position, it cannot exert all functions of a true K vitamin and the designation as vitamin K3 has been discouraged [WordNet 1.5]

b vitamin, b-complex vitamin, fat-soluble vitamin, vitamin, vitamin a, vitamin a1, vitamin a2, vitamin b, vitamin b complex, vitamin b1, vitamin b12, vitamin b2, vitamin b3, vitamin b5, vitamin b6, vitamin bc, vitamin c, vitamin d, vitamin deficiency, vitamin e, vitamin g, vitamin h, vitamin k, vitamin k1, vitamin k2, vitamin m, vitamin p, vitamin pill, water-soluble vitamin