Definition
A volatile liquid fuel refined from petroleum, used to power piston (reciprocating) aircraft engines. In aviation, it is most commonly aviation gasoline (avgas), a specially formulated grade such as 100LL, with a known weight of approximately 6 pounds per U.S. gallon for weight-and-balance calculations.
Plain English
The fuel that piston aircraft engines burn. For loading and weight calculations, pilots count it as about 6 pounds per gallon.
Context Anchor
Seen in weight-and-balance discussions when fuel is added, burned, drained, or included in the airplane’s total weight.
Derivation
From the early petroleum trade name 'gasolene', based on 'gas' (the volatile vapors it gives off) plus the chemical suffix '-ine/-ol'. The aviation point: gasoline is named for how readily it vaporizes — which is also why it ignites cleanly in a piston engine's cylinders.
Why Pilots Care
Incorrect fuel weight or type directly affects takeoff performance, climb rate, and landing distance, and can lead to engine damage if the wrong grade is used.
Intuition Check
Gasoline does not mean any aircraft fuel. Here it means the fuel for spark-plug aircraft engines; turbine or jet aircraft normally use jet fuel instead.
Example Sentence 1
After topping off the tanks, the pilot added 40 gallons of gasoline at 6 pounds per gallon, or 240 pounds, to the weight-and-balance sheet.
Example Sentence 2
Using the wrong grade of gasoline can cause detonation and engine failure at high power settings.