/ Dictionary / Index T theory of relativity: Meaning and Definition of Find definitions for: the'ory of relativ'ity Pronunciation: [key] — Physics. Physics. relativity (def. 2). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. theory of numbers theos. Related Content Daily Word Quiz: fidelity Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language