relativity vs relativity theory

relativity and relativity theory both are nouns.

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

As nouns, relativity and relativity theory are synonyms defined as:

relativity and relativity theory: (physics) the theory that space and time are relative concepts rather than absolute concepts

Other synonyms of relativity include Einstein's theory of relativity, theory of relativity.

relativity (noun)	relativity theory (noun)
the quality of being relative and having significance only in relation to something else	(physics) the theory that space and time are relative concepts rather than absolute concepts
(physics) the theory that space and time are relative concepts rather than absolute concepts