The traditional horsepower, equal to about 745.7 watts, as opposed to the metric horsepower, which is equal to about 735.5 watts. Note that the symbol bhp, with the lower case "b," is used for brake 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}