noun, plural Ouach·i·tas, (especially collectively) Ouach·i·ta for 2.
- a river flowing SE from W Arkansas through NE Louisiana to the Red River. 605 miles (975 km) long.
- a member of a former North American Indian tribe, apparently of the Caddoan stock, of NE Louisiana.
- a river in the S central US, rising in the Ouachita Mountains and flowing east, south, and southeast into the Red River in E Louisiana. Length: 974 km (605 miles)