| Acronym | Meaning |
| FPS | Feet Per Second |
| MIC | Microphone |
| LSM | Loader Select Modification |
| IPSC | Ice Protection System Controler |
| SLS | Sea Level Standard |
| SMS | Surface Missile System |
| PVS | Periscope View Simulators (associated With 21a Series) |
| WWMCCS | Worldwide Military Command And Control System |
| POM | Program Objective Memorandum |
| CPT | Cockpit Procedure Trainer |