from Choctaw, literally "red people," from okla "nation, people" + homma "red." Coined by Choctaw scholar Allen Wright, later principal chief of the Choctaw Nation, and first used in the Choctaw-Chickasaw treaty of April 28, 1866. Organized as a U.S. territory 1889; admitted as a state 1907. Related: Oklahoman.