Merriam-Webster Collegiate Dictionary - distrito federal

 geographical name  1. district E Argentina largely comprising capital city of Buenos Aires area 77 square miles (199 square kilometers), population 2,960,976  2. — see federal district 1  3. (or Federal District) district central Mexico including capital city of Mexico City area 579 square miles (1500 square kilometers), population 8,235,744  4. (or Federal District) district N Venezuela including capital city of Caracas area 745 square miles (1937 square kilometers), population 2,103,661