Definitions for "Brake Horsepower"
The horsepower required to drive the compressor at rated conditions.
It is the measure of an engine's horsepower without the loss in power. It is more than the actual horsepower delivered to the driving wheels.
Although theoretically equal to standard horsepower, "brake" horsepower specifies that a specific engineering process was used to arrive at that horsepower number. (See also: Horsepower and Torque)