1) aviation gasoline
2) avgas
a motor spirit prepared especially for aviation piston engines, with an octane number suited to the type of engine, varying from 80 to 145 octane number, and a freezing point of -60°C
GRM: n. (1,2)
USG: abbreviated form (2)
References:
SEE petrol
SEE gas
SEE gasoline

ENERGY TERM COURTESY OF ENERGY.EU