Literally, alphabet soup is a kind of soup containing noodles shaped like the letters of an alphabet.
In the metaphorical sense, the term is used to describe an abundance of abbreviations or acronyms. In this sense, the term goes back at least as far as the New Deal of Franklin D. Roosevelt.
In the United States one of the most common targets of the term is the Federal Government on account of the mulititude of agencies that it has spawned, including the NSA, CIA, FBI, USSS, BATF, DEA and INS. However, the citizens of the United States generally seem to adore abbreviations, even for such diverse items as the titles of movie films (e.g. MI2, or T3), and historical events (e.g. Y2K, or 9/11).
