/ Dictionary / Index T therein: Meaning and Definition of Find definitions for: there•in Pronunciation: (âr"in'), [key] — adv. in or into that place or thing. in that matter, circumstance, etc. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: therein (Thesaurus) therefrom thereinafter Related Content Daily Word Quiz: penchant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language