serum vs liquid body substance

serum and liquid body substance both are nouns.

Word	Noun	Adjective	Verb	Adverb
serum	Yes	No	No	No
liquid body substance	Yes	No	No	No

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

serum: an amber, watery fluid, rich in proteins, that separates out when blood coagulates
liquid body substance: the liquid parts of the body

Other hypernyms of serum include bodily fluid, body fluid, humor, humour.

serum (noun)	liquid body substance (noun)
an amber, watery fluid, rich in proteins, that separates out when blood coagulates	the liquid parts of the body