Watt is a unit of power in the International System of Units, abbreviated as W. It is named after the Scottish engineer James Watt, who made significant contributions to the development of the steam engine. One watt is defined as the rate at which work is done when one ampere of current flows through an electrical potential difference of one volt. The watt is commonly used to measure the power consumption of electrical devices, as well as the power output of engines and other mechanical systems. It is a fundamental unit of measurement in the field of physics and engineering.