/ Dictionary / Index T third house: Meaning and Definition of Find definitions for: third' house' Pronunciation: [key] — Informal. (sometimes caps.)Informal. a legislative lobby. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. thirdhand Third International Related Content Daily Word Quiz: procrastinate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language