Old World monkey vs Cercopithecidae

Old World monkey and Cercopithecidae both are nouns.

Word	Noun	Adjective	Verb	Adverb
Old World monkey	Yes	No	No	No
Cercopithecidae	Yes	No	No	No

Old World monkey (noun)	Cercopithecidae (noun)
of Africa or Arabia or Asia; having nonprehensile tails and nostrils close together	Old World monkeys: guenon, baboon, colobus monkey, langur, macaque, mandrill, mangabey, patas, proboscis monkey