Irradiance is the amount of radiant flux per unit area. This term is commonly used in physics and astronomy to describe the amount of energy that flows through a given surface. Some synonyms for irradiance include radiant intensity, radiant power, and radiant flux density. These terms all refer to the amount of energy that is transferred through a specific area. Additionally, irradiance may be measured in different units, such as watts per square meter or microwatts per square centimeter. Regardless of the unit of measurement, irradiance is an important concept in many areas of science and technology, including solar energy and environmental monitoring.