Siouan or Siouan–Catawban is a language family of North America that is located primarily in the Great Plains of North America with a few outlier languages in the east.
Noun 1. a family of North American Indian languages spoken by the Sioux (synonym) Siouan (hypernym) Amerind, Amerindian language, American-Indian language, American Indian, Indian (hyponym) Biloxi