a family of North American languages including Sioux, probably related to Iroquoian
adjective
2.
of or relating to the Sioux peoples or languages
Siouan in American English
(ˈsuːən)
noun
1.
a Native American language family formerly widespread from Saskatchewan to the lower Mississippi, also found in the Virginia and Carolina piedmont, and including Catawba, Crow, Dakota, Hidatsa, Mandan, Osage, and Winnebago
2.
a member of one of the Siouan-speaking peoples
adjective
3.
of or pertaining to the Sioux or the Siouan languages