Plain English Meaning
A part of the engine that slows the air down so its pressure goes up before it reaches the place where fuel is burned.
Full Definition
A section or component of an engine or duct system in which fast-moving air is slowed down, causing its static pressure to rise. In a turbine engine, the diffuser sits between the compressor and the combustion chamber, slowing the high-velocity airflow leaving the compressor so combustion can occur in a more stable, higher-pressure environment.
Context Anchor
Seen in aircraft engine maintenance, especially in turbine engines between the compressor and the burning section of the engine.