from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The actual or useful horsepower of an engine, usually determined from the force exerted on a friction brake or dynamometer connected to the drive shaft.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The useful horsepower of an engine as measured at its drive shaft.
from the GNU version of the Collaborative International Dictionary of English
- the net effective power of a prime mover, as a steam engine, water wheel, etc., in horse powers, as shown by a friction brake. See Friction brake, under Friction.
The term refers to a method of measuring the usable power of an engine by connecting a brake to the drive shaft of the engine. Other methods have been developed but the term remains. (Wiktionary)