Iguassu Falls - Brazil - Airport symbol (OAG)
Iminoglycinuria - Medicine (MELL)
Infantile Gastroenteritis Virus - Medicine (PDAA)
Instituto Geografico Universitario - University Geographic Institute (GIS)
Interfaz Grafica de Usuario - Graphical User Interface
Internationale Gewerbeunion - International Association of Crafts and Small and Medium Sized Enterprises - IACME - Berne, Switzerland (EAIO)
International Gas Union - See also UIIG (EAIO)
International Geographical Union - ICSU - Edmonton, AB (EA)
International Geophysical Union