Mach number Regulation
Mach number means the ratio of true airspeed to the speed of sound.
Also defined in 3 more sources
A measurement of speed based on the ratio of the speed of the aircraft to the speed of sound under the same atmospheric conditions. An airplane flying at Mach 1 is flying at the speed of sound.
Guidance: Aviation Maintenance Technician Handbook — Airframe, p. G-21
The ratio of the speed of an object through the air to the speed of sound under the same atmospheric conditions. An object traveling at the speed of sound is traveling at Mach one (M1.0).
Guidance: Aviation Maintenance Technician Handbook — Powerplant, p. G-17
The ratio of the true airspeed of the aircraft to the speed of sound in the same atmospheric conditions, named in honor of Ernst Mach, late 19th century physicist.
Guidance: Pilot's Handbook of Aeronautical Knowledge, p. G-18