Noun
An apparatus for measuring force or power; especially, muscular effort of men or animals, or the power developed by a motor, or that required to operate machinery.
Source: Webster's dictionaryAlso, with a chassis dynamometer or rolling road, power output is measured at the driving wheels. Source: Internet
A special railway car called a dynamometer car coupled behind the locomotive keeps a continuous record of the drawbar pull exerted, and the speed. Source: Internet
Although the output delivered to the driving wheels is less than that obtainable at the engine's crankshaft, a chassis dynamometer gives an indication of an engine's "real world" horsepower after losses in the drive train and gearbox. Source: Internet
More recently, an electrical brake dynamometer is used instead of a Prony brake. Source: Internet