This very good node refers only to horsepower. Horsepower, however, is only one particular unit of the more general concept power. Another good example is watts. 1 horsepower = 746 watts. A watt (actually newton-meters per second where horsepower is 33,000 pound-feet per minute) is the metric unit of power. We typically associate watts with electricity, but the laws of work and power hold true throughout physics no matter which units we prefer to use in a particular instance.