ˈsüən noun
( plural siouan or siouans )
Usage: usually capitalized
Etymology: Siou x + -an
1. : a language stock of central and eastern No. America including Crow, Hidatsa, Dakota, Chiwere, Winnebago, Dhegiha, Ofo, Biloxi, Tutelo, Catawba
2.
a. : a group of peoples speaking Siouan languages — called also Sioux
b. : a member of such peoples — called also Sioux