What term is used to refer to three times the speed of sound?

The term that refers to three times the speed of sound is known as Mach 3. In aerodynamics, the Mach number is a dimensionless unit used to represent the speed of an object in relation to the speed of sound in the surrounding medium. Therefore, when an object is moving at Mach 3, it means it is traveling at a speed that is three times greater than the speed of sound, which is approximately 343 meters per second at sea level in standard conditions.

Mach 2 refers to two times the speed of sound, while supersonic is a broader category encompassing any speed above Mach 1, not specifically three times the speed of sound. Hypervelocity generally refers to speeds significantly higher than those encountered in supersonic flights, often above Mach 5, and is used in contexts like re-entry velocities of spacecraft. Therefore, the specific designation of Mach 3 accurately identifies the speed of three times that of sound.