(physics) the theory that space and time are relative concepts rather than absolute concepts WordNet 3.0 & Open English WordNet

The theory of relativity usually encompasses two interrelated physics theories by Albert Einstein: special relativity and general relativity, proposed and published in 1905 and 1915, respectively. Wikipedia

A general treatment that refers to both special relativity and general relativity Wikipedia Disambiguation

Two interrelated physics theories by Albert Einstein Wikidata

Theory of Albert Einstein, composed by two scientific theories in physics: special relativity and general relativity. These theories were conceived in order to explain the fact that electromagnetic waves do not conform to the Newtonian laws for motion (source: Wikipedia). OmegaWiki

Either of two theories (special relativity or general relativity) developed by German-American physicist Albert Einstein. Also called Einsteinian relativity. Wiktionary

The theories of special relativity and general relativity, two theories in physics developed mainly by Albert Einstein at the beginning of the 20th century from which several important results such as the equivalence of matter and energy and the Einstein field equations are derived. Wiktionary

Special and general relativity. Wiktionary (translation)