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[hawrs-pou-er] /ˈhɔrsˌpaʊ ər/
a foot-pound-second unit of power, equivalent to 550 foot-pounds per second, or 745.7 watts.
Informal. the capacity to achieve or produce; strength or talent:
The university's history faculty is noted for its intellectual horsepower.
Origin of horsepower
First recorded in 1800-10; horse + power Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for horsepower
Contemporary Examples
Historical Examples
  • The motor is a double-cylinder two-cycle one, of ten horsepower.

  • And I will measure the energy I use in terms of sun-powers, not horsepower.

    Invaders from the Infinite

    John Wood Campbell
  • In fact, nothing but a machine of horsepower could have accomplished that.

    The Desert Home Mayne Reid
  • Geilsgrefte, horsepower, was best exerted by a horse, he thought.

    Blind Man's Lantern Allen Kim Lang
  • But let us take five horsepower as a desirable minimum in this instance.

    Electricity for the farm Frederick Irving Anderson
  • Motors are rated by horsepower, and generators are rated by kilowatts.

    Electricity for the farm Frederick Irving Anderson
British Dictionary definitions for horsepower


an fps unit of power, equal to 550 foot-pounds per second (equivalent to 745.7 watts)
a US standard unit of power, equal to 746 watts
Abbreviation HP, h.p
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for horsepower

1806, from horse (n.) + power (n.); established by Watt as the power needed to lift 33,000 pounds one foot in one minute, which is actually about 1.5 times the power of a strong horse.

Online Etymology Dictionary, © 2010 Douglas Harper
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horsepower in Science
A unit that is used to measure the power of engines and motors. One unit of horsepower is equal to the power needed to lift 550 pounds one foot in one second. This unit has been widely replaced by the watt in scientific usage; one horsepower is equal to 745.7 watts.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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horsepower in Culture

horsepower definition

A unit of power equal to about 746 watts.

Note: The horsepower is used to measure the power of engines.
Note: This term was coined by James Watt, who invented a new type of steam engine in the eighteenth century. Watt found that the horse could do a certain amount of work per second; when he sold his steam engines, this measurement allowed him to estimate the worth of an engine in terms of the number of horses it would replace. Therefore, a six-horsepower engine was capable of replacing six horses.
The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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