hp
Horsepower
Horsepower is a unit of power used primarily to measure the output of engines and motors. One mechanical horsepower equals approximately 745.7 watts. It is the standard unit for expressing car engine power in the United States and several other countries.
History
Horsepower was defined by James Watt in the late 18th century to compare the output of his steam engines with draft horses. He determined that a horse could do 33,000 foot-pounds of work per minute, which became the definition of one horsepower.