Plain English Meaning
A set of small, angled blades at the front of a jet engine's compressor that can pivot to steer incoming air onto the spinning compressor blades at the right angle. The angle changes automatically as engine conditions change, so the airflow always meets the blades smoothly.
Full Definition
A variable inlet guide vane is a movable, angle-adjustable vane positioned at the inlet of a turbine engine compressor that directs incoming airflow onto the first stage of compressor blades at the correct angle for the engine's current operating conditions. By rotating to change their pitch, VIGVs control how the air strikes the compressor, helping prevent compressor stalls across a wide range of power settings, airspeeds, and .