| Abbreviation | Definition |
|---|---|
| IFB | Invitation For Bid |
| IFC | Intelligence Fusion Center |
| IFC | Item For Collection |
| IFCS | Improved Fire Control System |
| IFD | Israel Defense Forces |
| IFE | Instrument Flight Examiner |
| IFF | Identification Friend or Foe |
| IFF | Identification, Friend or Foe |
| IFF | Integral Force Feedback |
| IFF/NCTR | Identification Friend or Foe/Non-Cooperative TaRget |
| IFF/SIF | Identification Friend or Foe/Selective Identification Feature |
| IFF/SIF | Identification, Friend or Foe/selective Identification Feature |
| IFFC | Integrated Fire and Flight Control |
| IFFG | Initial Follow on Forces Group |
| IFFN | Identification Friend, Foe, and Neutral |
| IFFN | Identification, Friend, Foe, or Neutral |
| IFFN | Identify Friend, Foe, and Neutral Forces |
| IFIS | Integriertes Fuhrangs und Information System ( German counterpart to CVC2) |
| IFM | Instantaneous Frequency Measurement |
| IFOG | Interferometric Fiber Optic Gyro |