horsepower - the mechanical engineering unit of power, equivalent to working at the rate of 33,000 ft lbf min?¹, or 42.41 Btu min?¹, or 745.70 watts. Abbreviation h.p. See cheval-vapeur for the metric equivalent. cheval-vapeur - the metric unit of horsepower, equivalent to 75 kgf m s?¹, 735.5 W or 0.986 hp. Abbrviation CV. Also known as Pferdestärke (PS), cheval (ch).