whey vs serum

whey and serum both are nouns.

Word	Noun	Adjective	Verb	Adverb
whey	Yes	No	No	No
serum	Yes	No	No	No

As nouns, serum is a hypernym of whey; that is, serum is a word with a broader meaning than whey:

whey: the serum or watery part of milk that is separated from the curd in making cheese
serum: an amber, watery fluid, rich in proteins, that separates out when blood coagulates

Other hypernyms of whey include blood serum.

whey (noun)	serum (noun)
watery part of milk produced when raw milk sours and coagulates	an amber, watery fluid, rich in proteins, that separates out when blood coagulates
the serum or watery part of milk that is separated from the curd in making cheese