A midwestern state in central United States; a border state during the American Civil War, Missouri was admitted to the Confederacy without actually seceding from the Union.

synonyms: MO, Mo., Show Me State.

Dutch: Missouri

The longest river in the United States; arises in Montana and flows southeastward to become a tributary of the Mississippi at Saint Louis:
— The Missouri and Mississippi Rivers together form the third longest river in the world.

synonym: Missouri River.

Dutch: Missouri

A member of the Siouan people formerly inhabiting the valley of the Missouri river in Missouri.

A dialect of the Chiwere language spoken by the Missouri.