Pronunciation: (mi-zoor'ē, -zoor'u), [key]
—pl. -sour•is, (esp. collectively) -sour•i for 3.
1. a state in the central United States. 4,917,444; 69,674 sq. mi. (180,455 sq. km). Cap.: Jefferson City. Abbr.: MO (for use with zip code), Mo.
2. a river flowing from SW Montana into the Mississippi N of St. Louis, Mo. 2723 mi. (4382 km) long.
3. a member of a North American Indian tribe belonging to the Siouan linguistic stock, located on the Missouri River in early historic times and now extinct as a tribe.
4. from Missouri, Informal.unwilling to accept something without proof; skeptical: I'm from Missouri--you'll have to show me that you're right.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.