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.
The US measurement system is a confusing matter and still holds itself apart from the metric system employed by most other countries. There are a few exceptions. Medical and scientific fields use the metric system, and many items for trade are now measured in the International System of Units (SI), also called the metric system.