A hygrometer is the device used to measure humidity. It quantifies the amount of moisture present in the air, providing readings in either relative humidity or absolute humidity. Various types of hygrometers exist, including mechanical hygrometers, which use materials that expand and contract with humidity changes, and electronic hygrometers, which rely on sensors to gauge moisture levels. Hygrometers play a crucial role in various applications, from meteorology and environmental control to industrial processes and HVAC systems. Accurate humidity measurement is essential for health, comfort, and optimal conditions in both residential and agricultural settings.