Definition
In a turbine engine compressor, a stage is one set of rotating blades (a rotor) followed by one set of stationary blades (a stator). Each stage progressively raises the pressure of the air passing through the compressor. Multiple stages are arranged in series to achieve the high pressure ratios required for combustion.
Plain English
One stage of a compressor is one pair of blade rows working together: a spinning row that pushes the air, and a fixed row right behind it that straightens the air and helps build pressure. Compressors stack many of these pairs in a line to keep squeezing the air tighter as it moves through.
Context Anchor
Seen in turbine engine descriptions, compressor inspection, and discussions of engine airflow and power production.
Derivation
The word stage comes from the Latin stare, meaning to stand or to be placed. In engineering it refers to one step in a series of steps. Each compressor stage is one step in the process of squeezing the air tighter and tighter.
Why Pilots Care
More stages generally mean a higher pressure ratio, which improves engine efficiency and thrust. Damage to even one stage (such as from a foreign object or a compressor stall) can degrade the performance of the entire engine, because each stage depends on the airflow delivered by the one before it.
Analogy
Think of the compressor like a staircase for air pressure. Each stage is one step that raises the air pressure a little more before the air moves to the next step.
Intuition Check
Do not read stage here as a time period or a phase of training. In this term, a stage is a physical section of the compressor that the air passes through.
Example Sentence 1
A modern axial-flow compressor may have ten or more stages, each adding a small amount of pressure to the air before it reaches the combustion section.
Example Sentence 2
Each additional stage of the compressor raises the overall pressure ratio delivered to the combustion section.