A milliwatt (mW) is a metric unit of power equal to one‑thousandth of a watt, used to quantify the rate at which energy is transferred or consumed in electrical and electronic systems. Because it measures very low‑level power output, the milliwatt is essential for evaluating the performance of tiny devices such as LEDs, laser diodes, sensors, and battery‑powered gadgets, as well as for precise scientific experiments that require accurate energy budgeting. Engineers and researchers rely on the mW scale to compare efficiency, troubleshoot circuitry, and design energy‑saving solutions, making it a cornerstone unit in both practical electronics and advanced scientific research.