/ Dictionary / Index T thereon: Meaning and Definition of Find definitions for: there•on Pronunciation: (âr"on', -ôn'), [key] — adv. on or upon that or it. immediately after that; thereupon. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: thereon (Thesaurus) thereof there's Related Content Daily Word Quiz: gregarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language