Definition from Wiktionary, the free dictionary
- A designation on prerecorded compact discs indicating that the contents were recorded and mixed in analog before being mastered to a digital medium; compare ADD, DAD, DDD.
Proper noun 
AAD (plural undefined)
AAD (plural AADs)
- Initialism of Aircraft Assignment Directive.
- Initialism of Anti-aircraft division.
- (historical) Initialism of armored automobie detachment.
- Initialism of army air defense.