theory of relativity vs event

theory of relativity and event both are nouns.

Word	Noun	Adjective	Verb	Adverb
theory of relativity	Yes	No	No	No
event	Yes	No	No	No

theory of relativity (noun)	event (noun)
(physics) the theory that space and time are relative concepts rather than absolute concepts	something that happens at a given place and time
	a phenomenon located at a single point in space-time; the fundamental observational entity in relativity theory
	a phenomenon that follows and is caused by some previous phenomenon
	a special set of circumstances