<Dl> <Dd> where </Dd> </Dl> <Dl> <Dd> D is the diameter (or bore) of the cylinder in inches </Dd> <Dd> n is the number of cylinders </Dd> </Dl> <Dd> D is the diameter (or bore) of the cylinder in inches </Dd> <Dd> n is the number of cylinders </Dd>

Where did the term brake horsepower come from