Siouan languages
Authors who call the entire family "Siouan" distinguish the two branches as "Western Siouan" and "Eastern Siouan" or as "Siouan-proper" and "Catawban". Others restrict the name "Siouan" to the western branch and use the name "Siouan–Catawban" for the entire family. Generally, however, the name "Siouan" is used without distinction.
Mandan
The English name "Mandan" is derived from the French-Canadian explorer Pierre Gaultier, Sieur de la Verendrye, who in 1738 heard it as "Mantannes" from his Assiniboine guides, which call the Mandan "Mayádąna". He had previously heard the earth lodge peoples referred to by the Cree as "Ouachipouennes", "the Sioux who go underground". The Assiniboine are Siouan speakers. Nearby Siouan speakers had exonyms similar to "Mantannes" in their languages, for instance, Teton "Miwáthaŋni" or "Miwátąni", Yanktonai "Miwátani", Yankton "Mawátani" or "Mąwátanį", Dakota "Mawátąna" or "Mawátadą", etc.