English abbreviations from iff-sif to ifr
- IFF/SIF (Identification Friend or Foe/Selective Identification Feature)
- IFFC (Integrated Fire and Flight Control)
- IFFCC (Integrated Flight and Fire Control Computer)
- IFFD (International Federation for Family Development)
- IFFN (Identification, Friend, Foe, or Neutral)
- IFIP (International Federation of Information Processing)
- IFIS (Integrated Functional Imaging System)
- IFJ (Ísafjörður Airport)
- IFL (Innisfail Airport)
- IFM (Instantaneous Frequency Measurement)
- IFMC (Iowa Foundation for Medical Care)
- IFMGA (International Federation of Mountain Guides Associations)
- IFMSA (International Federation of Medical Students' Associations)
- IFN (Esfahan Shahid Beheshti International Airport)
- IFNA (International Federation Netball Association)
- IFO (Identified Flying Object (see also UFO))
- IFOA (International Festival Of Authors)
- IFOB (International Friends Of Belize)
- IFOG (Interferometric Fiber Optic Gyro)
- IFOR (UN Implementation Force|| Institute for Operations Research||International Fellowship of Reconciliation)
- IFOV (Instantaneous Field of View)
- IFP (Laughlin/Bullhead International Airport)
- IFPA (Intermediate-Frequency Pre-Amplifier)
- IFPI (International Federation of Phonographic Industries)
- IFPRI (International Food Policy Research Institute)
- IFQT (Informal Qualification Test)
- IFR (Instrument Flight Rules)
