| Abbreviation | Definition |
|---|---|
| SITREP | SITuation REPort |
| SITSUM | Situation Summary |
| SITU | Situation |
| SIU | Sensor Interface Unit |
| SIU | Simulation Interface Unit |
| SIV | Special Interest Vessel |
| SIV | Special Interest Videos |
| SIV | Systems Integration Vehicle |
| SJA | Staff Judge Advocate |
| SJAB | St John Ambulance Brigade |
| SJFHQ | Standing Joint Force Headquarters |
| SJFHQ(CE) | Standing Joint Force Headquarters (Core Element) |
| SJFHQ-N | Standing Joint Force Headquarters - North |
| SJMS | St John's Military School |
| SJN | ignal-to-Jammer Noise |
| SJN | Signal-to-Jammer Noise |
| SJNMA | St John's Northwestern Military Academy |
| SJPO | Systems Joint Project Officer |
| SJS | Secretary, Joint Staff |
| SK | Schnellade Kanone |