/ Dictionary / Index M Monongahela: Meaning and Definition of Find definitions for: Mo•non•ga•he•la Pronunciation: (mu-nong"gu-hē'lu), [key] — n. a river flowing from N West Virginia through SW Pennsylvania into the Ohio River. 128 mi. (205 km) long. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: monongahela (Thesaurus) monomorphism mononuclear Related Content Daily Word Quiz: placid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language