Main Entry: Mach

Pronunciation: \ˈmäk\

Function: noun

: a usually high speed expressed by a Mach number <an airplane flying at Mach 2>

Mach \ˈmäḵ\ Ernst (1838–1916), Austrian physicist and philosopher. Mach established the basic principles of scientific positivism. In the 1870s he made classic studies on the perception of bodily rotation. Mach was also a pioneer in the study of supersonic projectiles and jets. In 1887 he described in a paper on projectiles in flight the angle between the axis of the projectile and the envelope of the waves produced. This angle forms the basis for the Mach number.