epoch vs astronomy

epoch and astronomy both are nouns.

Word	Noun	Adjective	Verb	Adverb
epoch	Yes	No	No	No
astronomy	Yes	No	No	No

epoch (noun)	astronomy (noun)
a period marked by distinctive character or reckoned from a fixed point or event	the branch of physics that studies celestial bodies and the universe as a whole
a unit of geological time that is a subdivision of a period and is itself divided into ages
(astronomy) an arbitrarily fixed date that is the point in time relative to which information (as coordinates of a celestial body) is recorded