As proper nouns the difference between arkansas and caddo
is that
arkansas is a state of the United States of America. Postal code: AR, capital: Little Rock while
Caddo is a confederacy of several southeastern Native American tribes, who inhabited much of what is now East Texas, western Louisiana and portions of southern Arkansas and Oklahoma in the sixteenth century.
As a noun Caddo is
a member of one of the Caddo tribes.