/ Dictionary / Index B Big Muddy River: Meaning and Definition of Find definitions for: Big' Mud'dy Riv'er Pronunciation: [key] a river in SW Illinois, flowing SW into the Mississippi. ab. 120 mi. (195 km) long. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Big Muddy big name Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language