What does GAST stand for?

Gast Manufacturing - NCIC construction equipment make code (NCIC)

Gastric (WDAA)

Gastronomia Espanola - Ministerio de Cultura - Spain - Information service or system (CRD)

Geraeteausgabestelle - Equipment distributing point - German military - World War II

Globally Averaged Surface Temperature

Greenwich Apparent Sidereal Time (PDAA)