Definition
A naturally occurring liquid mixture of hydrocarbons found in underground deposits, refined to produce aviation fuels, lubricating oils, hydraulic fluids, greases, and many other products used in aircraft operation and maintenance.
Plain English
Crude oil pumped from the ground that is processed into the fuels and oils aircraft run on.
Context Anchor
Seen in fuel, oil, lubrication, and aircraft maintenance discussions.
Derivation
From Latin petra (rock) and oleum (oil), literally 'rock oil' -- the name reflects that this oil is drawn out of rock formations underground.
Why Pilots Care
Aviation depends on refined petroleum products for safe engine operation; fuel quality affects performance and safety.
Intuition Check
Petroleum is not the same thing as gasoline. Petroleum is the raw underground oil source; gasoline, jet fuel, and engine oil are products made from it.
Example Sentence 1
Aviation gasoline and jet fuel are both refined from petroleum.
Example Sentence 2
Refineries turn petroleum into different grades of fuel suitable for piston and turbine engines.