Definition
In a reciprocating aircraft engine, a cylinder is the round, tube-shaped chamber in which a piston moves up and down to compress the fuel-air mixture, contain the combustion event, and transfer the resulting force to the crankshaft. The cylinder assembly typically includes the cylinder barrel, the cylinder head with intake and exhaust valves, and cooling fins on the outside.
Plain English
It is the round metal tube inside the engine where fuel and air are squeezed and burned to push a piston down. That push is what ultimately turns the propeller.
Context Anchor
Seen in aircraft engine descriptions, maintenance records, preflight inspections, and engine temperature discussions.
Derivation
From the Greek 'kylindros', meaning a roller or anything that rolls — referring to its round, tubular shape. The aviation meaning keeps that geometric sense: a round chamber that houses the piston.
Why Pilots Care
Each cylinder contributes directly to engine power; issues such as low compression or overheating can reduce performance or lead to engine failure.
Intuition Check
Do not think of cylinder only as a simple geometric shape. In an aircraft engine, a cylinder is a working engine part where compression, burning, heat, and power production happen.
Example Sentence 1
Most light training aircraft use a four-cylinder engine, with each cylinder firing in turn to keep the propeller spinning smoothly.
Example Sentence 2
During the annual inspection the mechanic performed a compression check on each cylinder.