/ Dictionary / Index R run-on sentence: Meaning and Definition of Find definitions for: run'-on sen'tence Pronunciation: [key] a written sequence of two or more main clauses that are not separated by a period or semicolon or joined by a conjunction. Also calledCf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. run-on run-out Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language