- Abbreviation of Adult.
- (astronomy education) Initialism of Astronomy Diagnostic Test.
- (audio recording) Initialism of Automatic Double Tracking.
- (computing) Initialism of Acknowledged Data Transfer.
- (computing) Initialism of Advanced DRAM Technology.
- (healthcare) Initialism of Admissions, Discharge, Transfer.
- (hiking) Initialism of American Discovery Trail.
- (military) Initialism of Accumulated Deployed Time.
- (military) Initialism of Active Duty for Training.
- (military) Initialism of Active Duty Tour.
- (military, weaponry) Initialism of Active Denial Technology.
- (programming) Initialism of abstract data type.
- (research) Initialism of Accelerated Degradation Testing.
- (traffic information) Initialism of Average Daily Traffic.
- Wikipedia on ADT
- Active Denial Technology -- globalsecurity.org -- "Vehicle-Mounted Active Denial System (V-MADS)"