What does 'turbulence' describe in aviation?

Turbulence in aviation refers specifically to rough, bumpy, or choppy air that an aircraft encounters during flight. This phenomenon occurs due to variations in wind speed and direction, which can be caused by several factors, including atmospheric pressure differences, weather fronts, and terrain. When an airplane moves through these irregular air currents, passengers and crew may experience sudden motion, which can feel uncomfortable.

Understanding turbulence is crucial because it affects flight safety and passenger comfort. Pilots are trained to handle turbulence and often receive reports about its location from air traffic control or other pilots, allowing them to navigate through or around it when possible. This concept distinguishes turbulence from the other choices, which describe different aviation circumstances that do not involve the specific experience of irregular air movement during flight.