What is the full form of DCA?

District of Columbia. This is the "space" that the capitol of the United States, Washington, sits in. It is not a state, nor is it a province. It is a separate place that is part of the United States, but not part of a state.

Another acronym is Direct Current. In the US, there are two forms of electrical current, Alternating current and Direct current. The average US home has alternating current as standard wiring. Direct current is used in automobiles and some electronics utilizing battery devices.