Horsepower (HP) is a unit of measurement used to quantify the power output of engines and motors. It was originally developed in the 18th century by the engineer James Watt to compare the power of steam engines to that of horses. One horsepower is equivalent to approximately 746 watts, which helps in understanding how much work an engine can perform over time. In practical terms, horsepower is commonly used to describe the power of vehicles, such as cars and motorcycles. Higher horsepower typically indicates a more powerful engine, which can lead to better acceleration and speed. However, other factors, such as weight and aerodynamics, also influence a vehicle's overall performance.