Plain English Meaning

When a fast jet flies near the speed of sound, the air over its wings starts behaving in unstable ways and the airplane begins to shake. That shaking is called Mach buffet.

Full Definition

A vibration or shaking of the airframe that occurs when an airplane approaches or exceeds its critical Mach number, caused by airflow over portions of the wing reaching supersonic speed and forming shock waves that disrupt the smooth flow of air over the wing surface.

Context Anchor

Encountered in high-speed and high-altitude discussions, especially when about operating near an airplane’s maximum safe .