| Abbreviation | Definition |
|---|---|
| INF | Intermediate Range Nuclear Forces |
| INFER | Impressive Nation Featuring Equal Rights |
| ING | In-active National Guard |
| INL | Idaho National Laboratory |
| INPO | Institute of Nuclear Power Operations |
| INS | Ignoring National Security |
| INS | Immigration and Naturalization Service |
| INSCOM | U.S. Army Intelligence and Security Command |
| INSS | Institute for National Strategic Studies |
| INTEL | In No Time Ever Liberal |
| INTERMACS | Interagency Registry for Mechanically Assisted Circulatory Support |
| INTERPOL | International Criminal Police Organization |
| INTERPOL | International Political and Economic Order Leaders |
| INTL | INTernaL |
| INTL | International |
| IOC | Independent Outpatient Clinic |
| IOC | Index Of Cooperation |
| IOC | Industry Overpowers Communism |
| IOP | Institute of Politics |
| IOTF | Industries Of The Future |