calcium vs factor IV

calcium and factor IV both are nouns.

Word	Noun	Adjective	Verb	Adverb
calcium	Yes	No	No	No
factor IV	Yes	No	No	No

As nouns, factor IV is a hyponym of calcium; that is, factor IV is a word with a more specific, narrower meaning than calcium:

calcium: a white metallic element that burns with a brilliant light; the fifth most abundant element in the earth's crust; an important component of most plants and animals
factor IV: ion of calcium; a factor in the clotting of blood

Other hyponyms of calcium include calcium ion.

calcium (noun)	factor IV (noun)
a white metallic element that burns with a brilliant light; the fifth most abundant element in the earth's crust; an important component of most plants and animals	ion of calcium; a factor in the clotting of blood