Subsonic

Subsonic refers to speeds below the speed of sound, approximately 343 meters per second (761 miles per hour) at sea level. In aviation and other fields, objects or vehicles moving at subsonic speeds experience different aerodynamic forces than supersonic or hypersonic speeds. Most commercial airplanes operate at subsonic speeds, which allow for efficient and stable flight. The term helps distinguish this speed range from faster regimes where shock waves and other complex phenomena occur. Essentially, subsonic is a way to describe movement that stays below the threshold where the sound barrier and related effects become significant.