Plain English Meaning

Aviation gasoline — the fuel used by piston-engine airplanes. It is not the same as the gasoline used in cars or the kerosene-based fuel used in jets.

Full Definition

A specialized high-octane gasoline formulated for use in piston-engine aircraft. AVGAS is distinct from automotive gasoline and from jet fuel: it is blended for stable performance at altitude, resistance to detonation under high cylinder pressures, and reliable vaporization across a wide temperature range. The most common grade in general aviation is 100LL (100 octane, ), which is dyed blue for identification.