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1.
Stands for Basic Underwater Demolition SEAL training. It is a 6 month military training program that must be passed to become an elite Navy SEAL. It is considered by many experts to be the hardest military training in the world. It is famous for the notorious Hell Week where recruits constantly train for 5 and 1/2 days with a maximum of 4 hours sleep during the entire week. Roughly 70 to 80 percent of BUD/S classes do not make it to graduation.
Billy thought he was a bad motherfucker and wanted to be a Navy SEAL but dropped out of BUD/S after the first week.
by Frogman187 December 08, 2008
 
2.
BUD/S stands for Basic Underwater Demoliton/SEAL training, and it is the first stepping stone on the path to becoming a United States Navy SEAL.

BUD/S contains three phases, with the 1st focusing on physical conditioning, the 2nd focusing on combat diving, and the 3rd on land combat. Arguably the hardest part of BUD/S is the five day long Hell Week. Hell Week puts each trainee to the test with only a few hours of sleep.

After BUD/S, prospective SEALs move on to Army Airborne School, SEAL Qualification Training, and other schools.
John Doe is in the third phase of BUD/S right now.
by John Desro March 11, 2007