Pronunciation: (mäk),[key] —n. 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. Abbr.: M Also,Mach.Also called mach number, Mach number. [after E. Mach]
Pronunciation: (mäk; Ger. mäkh),[key] —n. Ernst Pronunciation: (ernst),[key] 1838–1916, Austrian physicist, psychologist, and philosopher.