D.C. can be an abbreviation for many things, but it most commonly refers to the United States' capital city, Washington D.C. Synonyms for D.C. might include "the District," "Capital City," or simply "Washington." Other meanings for D.C. might include "Doctor of Chiropractic" or "Direct Current." Synonyms for "Doctor of Chiropractic" could be "chiropractic physician" or "chiropractor." "Direct Current" might have synonyms such as "steady current" or "unidirectional current." Depending on the context, there could be a variety of synonyms for the abbreviation D.C.