what does the term "the storm that saved washington" denote?
It refers to a sudden and heavy thunderstorm that put out the fires from the attack.
Burning of Washington
Less than 4 days after the attack began, a sudden, very heavy thunderstorm—possibly a hurricane—put out the fires. 
what does the dc in washington dc stand for District of Columbia. how is the place widely as? The capital city of the United States of America. what happened to this place in 1812? On August 24–25, 1814, in a raid known as the Burning of Washington, British forces invaded the capital during the War of 1812. what was the reason behind this raid? It was a result of the ongoing conflict between the United States and its allies, and the United Kingdom of Great Britain and Ireland and its allies. which other properties were a part of this raid? Multiple government and military buildings, including the White House (then called the "Presidential Mansion"), the Capitol building, as well as other facilities of the U.S. government.
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Burning of Washington [SEP] "The Storm that Saved Washington"
Less than 4 days after the attack began, a sudden, very heavy thunderstorm—possibly a hurricane—put out the fires. It also spun off a tornado that passed through the center of the capital, setting down on Constitution Avenue and lifting two cannons before dropping them several yards away and killing British troops and American civilians alike. Following the storm, the British troops returned to their ships, many of which were badly damaged. There is some debate regarding the effect of this storm on the occupation. While some assert that the storm forced their retreat, it seems likely from their destructive and arsonous actions before the storm, and their written orders from Cochrane to "destroy and lay waste", that their intention was merely to raze the city, rather than occupy it for an extended period.