Interchangeable File Format. A standard developed by Commodore for files on the Amiga. These are more generally used to describe ILBM images created by programs such as DPaint and sound samples (8SVX) etc. Found on http://www.amigahistory.co.uk/i.html
Identification Friend or Foe - Radio device fitted to aircraft in order to identify the aircraft as friendly when approaching home radar stations Found on https://www.encyclo.co.uk/local/20490
Identification, Friend or Foe: a system of transmitters and transponders that uses coded signals to distinguish between friendly and hostile aircraft. Found on https://www.infoplease.com/dictionary/iff