Cad·do 
(kădō)
(kădō)n. pl. Caddo or Cad·dos
1. A member of a Native American confederacy composed of numerous small tribes formerly inhabiting the Red River area of Louisiana, Arkansas, and eastern Texas and now located in central Oklahoma.
2. The Caddoan language of the Caddo.
[French, from Caddo kaduhdā·čuʔ, a major tribe of the Caddo confederacy.]