The effective power output of an engine, sometimes measured as the resistance a brake attached to the output shaft provides to an engine. See: Horsepower
Russ Rowlett (Director), How Many? A Dictionary of Units of Measurement, Center for Mathematics and Science Education University of North Carolina, USA 2005. http://www.unc.edu/~rowlett/units/dictA.html, (Unit of Meas and Covr Factors - Amer) {608}