DDD

DDD can refer to, among others:

Data Display Debugger, a popular graphical user interface for command-line debuggers
Delta Delta Delta, a national collegiate sorority
Direct distance dialing, a telephony innovation that enabled subscribers to call long distance numbers without having to go though an operator
Die deterioration doubling, a common form of mint-made error on coins that results from degradation of the die used to strike the coin
Defined Daily Doses - a World Health Organisation statistical measure of drug use
Digital, digital, digital, a "pure digital" recording that is recorded, mastered, and transferred digitally
DDD is an album by Poster Children named after the pure digital recording process
Dichloro-diphenyl-dichloroethane, a breakdown product of DDT
Detailed design document, a software development document that describes what the software will do and how it will be designed