Mach
noun /mɑːk/, /mæk/
/mɑːk/, /mæk/
[uncountable]- (often followed by a number) a measurement of speed, used especially for aircraft. Mach 1 is the speed of sound.
- a fighter plane with a top speed of Mach 3 (= 3 times the speed of sound)
Word Origin1930s: named after E. Mach (1838-1916), Austrian physicist and philosopher of science.