Arkansas
wiktionary
From the name of the Arkansas River, from French Arcansas, a (plural) designation of either a Siouan tribe or the Quapaw. [1] This designation is sometimes claimed to derive from a Quapaw word *akakaze(“land of downriver people”) or a Lakota/Dakota word *akakaze(“people of the south wind”); more likely, it derives from a Siouan ethnonym cognate to Kansa (whence also the name of the state of Kansas). [1]
etymonline
Arkansas
organized as a U.S. territory 1819, admitted as a state 1836; it was named for the Arkansas River, which was named for a Siouan tribe.
The spelling of the term represents a French plural, Arcansas, of a name applied to the Quapaw people who lived on the Arkansas River; their name was also written in early times as Akancea, Acansea, Acansa (Dickinson, 1995). This was not the name used by the Quapaws themselves, however. The term /akansa/ was applied to them by Algonquian speakers; this consists of /a-/, an Algonquian prefix found in the names of ethnic groups, plus /kká:ze, a Siouan term referring to members of the Dhegiha branch of the Siouan family. This stem is also the origin for the name of the Kansa tribe and of the state of Kansas; thus the placenames Arkansas and Kansas indirectly have the same origin. [William Bright, "Native American Placenames of the United States," 2004]
The silent final -s, perhaps originally from the French pronunciation, was made official in 1881 by an act of the state legislature.
