Definition
An engine-driven air compressor that increases the pressure of the air delivered to the cylinders of a piston engine, allowing the engine to produce more power and to maintain sea-level power at higher altitudes where the air is thinner.
Plain English
A pump, driven by the engine itself, that squeezes more air into the cylinders so the engine can keep making strong power even when flying high where the air is thin.
Context Anchor
You will see this term in discussions of piston-engine power, high-altitude performance, and engine operating limits.
Derivation
From 'super-' (above, beyond) and 'charge' (to load or fill). The engine cylinders are being filled with more air than they would naturally draw in, so they are 'super-charged.'
Why Pilots Care
Maintains sea-level horsepower at altitude, improving climb rate and high-altitude cruise performance in normally aspirated engines.
Analogy
Like a mechanical fan that rams extra air into a fire, allowing it to burn hotter and stronger than it could on its own.
Grounding Statement
At altitude, a supercharger helps the engine breathe denser air than it could get from the outside air alone.
Intuition Check
A supercharger does not create power by itself. It helps the engine make power by forcing more air into the cylinders.
Example Sentence 1
The aircraft's supercharger allowed it to maintain full rated power up to 10,000 feet despite the thinner air at that altitude.
Example Sentence 2
During the preflight inspection the mechanic verified that the supercharger produced the correct boost at idle.