When we check cars out, most times we've read specs like 120 horsepower. But what does that mean? Does it mean the car has the strength of 120 horses put together?
Horsepower is actually an arbitrary set of criteria used as a form of reference for an abstract yet quantifiable thing. The term came from a time where people were getting around with the steam engines.
Check out the infographic from Jalopnik below:

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Jalopnik]