era vs Cenozoic era

era and Cenozoic era both are nouns.

Word	Noun	Adjective	Verb	Adverb
era	Yes	No	No	No
Cenozoic era	Yes	No	No	No

era (noun)	Cenozoic era (noun)
a period marked by distinctive character or reckoned from a fixed point or event	approximately the last 63 million years
a major division of geological time; an era is usually divided into two or more periods