What do the letters D. C. Stand for? Why do people say " Washington, D. C." when they speak about the US capital? Ответь те на вопросы! Желательно сразу на английском!

Washington was the first president of the United States of America and there are two places that are called after him. One of them is Washington. It is one of the states in the United States of America. The capital of the United States is in a state which is called Columbia. That is why we add D. C. when we speak about the capital. The name of the capital is Washington D. C. which means District (D) of Columbia (C). It we don't us D. C it will mean the state.