vitamin K vs vitamin K3

vitamin K and vitamin K3 both are nouns.

Word	Noun	Adjective	Verb	Adverb
vitamin K	Yes	No	No	No
vitamin K3	Yes	No	No	No

As nouns, vitamin K3 is a hyponym of vitamin K; that is, vitamin K3 is a word with a more specific, narrower meaning than vitamin K:

vitamin K: a fat-soluble vitamin that helps in the clotting of blood
vitamin K3: a synthetic chemical compound that is a form of vitamin K, it is an analog of 1,4-naphthoquinone with a methyl group in the 2-position

Other hyponyms of vitamin K include phylloquinone, phytonadione, vitamin K1, menadione.

vitamin K (noun)	vitamin K3 (noun)
a fat-soluble vitamin that helps in the clotting of blood	a synthetic chemical compound that is a form of vitamin K, it is an analog of 1,4-naphthoquinone with a methyl group in the 2-position