| Abbreviation | Definition |
|---|---|
| ALT | Active Leap Technology |
| ALT | Administrative Lead Time |
| ALT | Alternate |
| ALT | Altitude |
| ALT | Anarchists, Lunatics, and Terrorists |
| ALTAIR | Advanced Research Projects Agency Long Range Tracking and Instrumentation Radar |
| ALTB | Airborne Laser Test Bed |
| ALTC | Army Logistic Training Centre |
| ALTD | Airborne Laser Target Designator |
| ALTERS | Allied Telecommunications Record System |
| ALTM | ATCCS (Army Tactical Command and Control System) Layered Telecommunications Model |
| ALTM | ATCCS Layered Telecommunications Model |
| ALTROUTE | Alternate Routing |
| ALTS | Automatic Laser Tracking System |
| ALTTSC | ALTernate Tomahawk Strike Coordinator |
| ALV | Autonomous Land Vehicle |
| ALWNA | Army Landwarnet Architecture |
| ALWT | Advanced Light Weight Torpedo |
| AM | Acknowledgment Message |
| AM | Air Mobile |