"压气机级" can be translated as "compressor stage" in English.
In the context of turbomachinery, such as gas turbines or jet engines, a "compressor stage" refers to a specific section or level within the compressor where the air is compressed to a higher pressure before entering the combustion chamber. Each stage typically consists of a set of rotating blades (rotor) and stationary vanes (stator) that work together to increase the pressure and temperature of the incoming air.