linguistic:paraphrasing
Etymology

The Sioux people refer to their whole nation of people (sometimes called the Great Sioux Nation) as the Očhéthi Šakówiŋ (meaning "Seven Council Fires"). Each fire symbolises an oyate (people or nation). Today the seven nations that comprise the Očhéthi Šakówiŋ are:

They are also referred to as the Lakota or Dakota based on dialect differences. In any of the dialects, Lakota or Dakota translates to mean "friend" or "ally" referring to the alliances between the bands.

The name "Sioux" was adopted in English by the 1760s from French. It is abbreviated from the French Nadouessioux, first attested by Jean Nicolet in 1640. The name is sometimes said to be derived from " Nadowessi " (plural " Nadowessiwag "), an Ojibwe exonym for the Sioux meaning "little snakes" or enemy (compare nadowe "big snakes", used for the Iroquois). The French pluralized the Ojibwe singular " Nadowessi " by adding the French plural suffix " oux " to form " Nadowessioux ", which was later shortened to " Sioux ". The Proto-Algonquian form *na·towe·wa, meaning "Northern Iroquoian", has reflexes in several daughter languages that refer to a small rattlesnake (massasauga, Sistrurus). An alternative explanation is derivation from an (Algonquian) exonym na·towe·ssiw (plural na·towe·ssiwak), from a verb * -a·towe· meaning "to speak a foreign language". The current Ojibwe term for the Sioux and related groups is Bwaanag (singular Bwaan), meaning "roasters". Presumably, this refers to the style of cooking the Sioux used in the past.

In recent times, some of the tribes have formally or informally reclaimed traditional names: the Rosebud Sioux Tribe is also known as the Sičháŋǧu Oyáte, and the Oglala often use the name Oglála Lakȟóta Oyáte, rather than the formal Oglala Sioux Tribe or OST. The alternative English spelling of Ogallala is considered incorrect.