Definition from Wiktionary, the free dictionary
- (organic chemistry) Dichlorodiphenyldichloroethane, an insecticide related to DDT
- (telecommunications) Direct distance dialing, a network-provided service that enables non-local telephone calls to be made without operator assistance
- Die-deterioration doubling, a common form of mint-made error on coins that results from degradation of the die used to strike the coin
- A designation on prerecorded compact discs indicating a "full digital recording" (recorded, mixed and mastered in digital); compare AAD, ADD, DAD.