antiserum vs serum

antiserum and serum both are nouns.

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

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

antiserum: blood serum containing antibodies against specific antigens; provides immunity to a disease
serum: an amber, watery fluid, rich in proteins, that separates out when blood coagulates

Other hypernyms of antiserum include blood serum.

antiserum (noun)	serum (noun)
blood serum containing antibodies against specific antigens; provides immunity to a disease	an amber, watery fluid, rich in proteins, that separates out when blood coagulates