The term SIOUAN INDIAN refers to a group of Native American tribes that speak the Siouan language. The crossword solutions for this term include PONCA (5 letters), CROW (4 letters), OSAGE (5 letters), OTOE (4 letters), OTO (3 letters), OMAHA (5 letters), OTOES (5 letters), and DAKOTA (6 letters). These tribes are located in the Great Plains region of the United States and Canada, and include the Ponca, CROW, Osage, Otoe, Omaha, Otoes, and DAKOTA tribes.