"Horse Power" is a word in ENGLISH

A machine worked by a horse, for driving other
machinery; a horse motor.

A unit of power, used in stating the power required to
drive machinery, and in estimating the capabilities of animals or steam
engines and other prime movers for doing work. It is the power required
for the performance of work at the rate of 33,000 English units of work
per minute; hence, it is the power that must be exerted in lifting
33,000 pounds at the rate of one foot per minute, or 550 pounds at the
rate of one foot per second, or 55 pounds at the rate of ten feet per
second, etc.

The power which a horse exerts.