Siouan people of the American Midwest, 1806, from French, a variant of Kansa (itself in English from 1722), from /kká:ze, a Siouan term referring to members of the Dhegiha branch of the Siouan family. Compare Arkansas. The Siouan word is a plural. Established as a U.S. territory in 1854 and named for the river, which is named for the people; admitted as a state 1861. Related: Kansan; Kansian, used by Whitman and a few others, seems not to have thrived.