quadrivium vs Middle Ages

quadrivium and Middle Ages both are nouns.

Word	Noun	Adjective	Verb	Adverb
quadrivium	Yes	No	No	No
Middle Ages	Yes	No	No	No

quadrivium (noun)	Middle Ages (noun)
(Middle Ages) a higher division of the curriculum in a medieval university involving arithmetic and music and geometry and astronomy	the period of history between classical antiquity and the Italian Renaissance