What does GUG stand for?

Empresa Guatemalteca de Aviacion - Guatemala - ICAO designator (FAAC)

Guanine Uracil Guanine - A triplet of bases coding for the amino acid, valine (EES)

Guarding - Telegraphy (PCTE)

Guari - Papua New Guinea - Airport symbol (OAG)

Gulf Boats Inc., Pass Christian, MS - Manufacturer code for watercraft hull identification number (USCG)

N'Guigmi - Niger - Airport symbol (AD)

Paraguayan Guarani - Language code (ETLW)