Fr, contr. < Nadouessioux, pl. < Ottawa dialect of nadowe-is-iw, naadoweesiwag, an ethnic name, lit., adder: applied in variant forms in different Algonquian languages to a number of non-Algonquian groups
a. A group of Native American peoples, also known as the Dakota, inhabiting the northern Great Plains from Minnesota to eastern Montana and from southern Saskatchewan to Nebraska. Present-day Sioux populations are located mainly in North and South Dakota.