District of Columbia

WordReference Random House Unabridged Dictionary of American English © 2026

Dis′trict of Colum′bia, 

1. Place Names a federal area in the E United States, on the Potomac, coextensive with the federal capital, Washington. 637,651;
   69 sq. mi. (179 sq. km). Abbr.: DC (for use with zip code), D.C.

Collins Concise English Dictionary © HarperCollins Publishers::

District of Columbia noun

1. a federal district of the eastern US, coextensive with the federal capital, Washington. Pop: 564 326 (2003 est). Area: 178 sq km (69 sq miles)
   Abbreviation: D.C., (with zip code) DC