How is one watt related to horsepower?

The watt and horsepower are both units used to measure power, which is the rate at which work is performed.12

In the International System of Units (SI), one watt is defined as one joule of work performed per second. The relationship between the two units is defined such that one horsepower is equivalent to 746 watts.321

The unit of the watt is named in honor of the Scottish engineer James Watt, who also adopted the horsepower unit in the late 18th century after conducting experiments with dray horses. While horsepower is traditionally based on the British Imperial System—defined as 33,000 foot-pounds of work per minute—the watt serves as the standard SI unit for measuring the rate of energy transfer.3142