Definition
An engine-driven air compressor that pumps outside air into the sealed cabin of a pressurized aircraft to maintain a higher pressure inside the cabin than the surrounding atmosphere at altitude.
Plain English
A pump that forces extra air into the cabin so the people inside can breathe comfortably even when the aircraft is flying very high where the outside air is too thin.
Context Anchor
Seen in discussions of pressurized aircraft, cabin air systems, and high-altitude flight.
Derivation
Supercharger comes from 'super' (above, beyond) and 'charge' (to load or fill). A supercharger fills something beyond its natural state. A cabin supercharger fills the cabin with more air than it would naturally hold at altitude.
Why Pilots Care
Allows safe high-altitude flight without hypoxia or discomfort by keeping cabin pressure within normal breathing range.
Analogy
It is like using a pump to add air to a tire. The pump takes outside air and squeezes it into a smaller space at higher pressure.
Intuition Check
Do not confuse a cabin supercharger with an engine supercharger. A cabin supercharger helps maintain cabin air pressure; an engine supercharger helps the engine receive more air.
Example Sentence 1
The cabin supercharger maintained a comfortable cabin altitude of 8,000 feet while the aircraft cruised at 25,000 feet.
Example Sentence 2
A failure of the cabin supercharger required an immediate descent to an altitude where outside air pressure remained adequate.