Horsepower

How to spell horsepower

10 letters · 3 syllables

How to pronounce horsepower

Say the part in capitals loudest.

What does horsepower mean?

1. nounA unit measuring the rate at which mechanical work is done, especially the output of an engine or motor.

Horsepower in a sentence

• The sports car produces more horsepower than the family saloon.

• Mechanics measured the engine's horsepower on a test bench.

Where does horsepower come from?

Language of origin: Germanic

This word is a transparent English compound joining 'horse', a native Old English word (hors), with 'power', which came into Middle English from Old French poeir, ultimately from Latin posse meaning 'to be able'. The term was coined in the late 1700s by the Scottish engineer James Watt, who needed a way to sell his steam engines to mine owners by comparing their output to the draught horses the engines would replace. Watt estimated how much weight a working horse could lift over a given time and fixed that figure as one unit, giving buyers an instantly understandable benchmark. The choice was a marketing masterstroke, because it let a customer picture a team of living horses doing the same labour as the new machine. The spelling stays simple precisely because both halves are ordinary everyday words, so the only thing to remember is that it is written as a single closed compound, not two words or a hyphenated form.

How the word is built

• horse (the animal)
• power (capacity to do work); a compound coined as a unit of mechanical power