- a number indicating the ratio of the speed of an object to the speed of sound in the medium through which the object is moving. Abbreviation: M
- Ernst [ernst] /ɛrnst/, 1838–1916, Austrian physicist, psychologist, and philosopher.
- short for Mach number
- Ernst (ɛrnst). 1838–1916, Austrian physicist and philosopher. He devised the system of speed measurement using the Mach number. He also founded logical positivism, asserting that the validity of a scientific law is proved only after empirical testing
measure of speed relative to the speed of sound (technically Mach number), 1937, named in honor of Austrian physicist Ernst Mach (1838-1916).
- Austrian physicist and philosopher who experimented with supersonic projectiles and the flow of gases, obtaining early photographs of shock waves and gas jets. His work laid an important foundation for later developments in the science of projectiles and aeronautical design, and the Mach number and Mach bands were named for him.