horsepower

     Car engines are still described in terms of horsepower. Which means, well, horsepower--as in how many horses would you have to hitch to your wagon to get the same amount of power that the particular engine can deliver. If an engine is described as "300 hp", the manufacturer is claiming that it is as powerful as 300 horses hitched together. I'm not sure that anyone has ever hitched 300 horses together, but you get the point. The term has not become obsolete, as people now use it to compare one engine with another, instead of comparing the engines to horses, as they might have done 100 years ago.