| Abbreviation | Definition |
|---|---|
| IMU | Intermatrix Unit |
| IMU | International Measurements Unit |
| IMU | International Monitoring Unit |
| IMWRF | Installation Morale, Welfare, and Recreation Fund |
| IN | Air Force Component Intelligence Officer (Staff) |
| IN | Impulse Noise |
| IN | Infantry |
| IN | Instructor |
| INA | Indian National Army |
| INC | Incorporated |
| INC | Interface Network Controller |
| INC | INternet Controller |
| INCA | Intelligence Communications Architecture |
| INCERFA | Uncertainty Phase (ICAO) |
| INCNR | Increment Number |
| INCO | Indian Non-Commissioned Officer |
| INCONREP | Intra-CONtinental United States Movement REPort |
| INCONREP | Intra-Continental US Movement Report |
| INCS | Internet Controllers |
| INCSEA | Incidents At Sea |