There are several synonyms for the acronym "DC", which is commonly understood to refer to the capital city of the United States, Washington, DC. One alternative is simply "Washington", while others include the formal "District of Columbia" or the more colloquial "the District". Some people may also use "DC Metro" to refer to the wider metropolitan area that includes the city and its suburbs. In certain contexts, "DC" may also stand for "Direct Current", a type of electrical current that flows in only one direction, or "Detective Comics", a major comic book publisher known for creating iconic superheroes such as Batman.