Southpaw is a boxing term that designates the stance where the boxer has his right hand and right foot forward, leading with right jabs, and following with a left cross right hook. Southpaw is the normal stance for a left-handed boxer.
Because the American system of measurement is very similar to the British imperial system, units are also commonly referred to as imperial units. The units have many different origins.
Unit of measurement is a definite magnitude of a physical quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same physical quantity. Different systems of units used to be very common.