Photometry is the measurement of light and its properties. Several synonyms for photometry include radiometry, spectrophotometry, and luminescence. Radiometry emphasizes the measurement of electromagnetic radiation, while spectrophotometry is a method of measuring the amount of light absorbed by a substance. Luminescence specifically involves the emission of light as a result of a chemical or biological reaction. Other synonyms for photometry include light measurement, light quantification, and illuminance measurement. Regardless of the synonym used, photometry is an important tool in a variety of fields, including astronomy, photography, and optics. Accurate measurements of light can provide valuable insights into the properties and behavior of materials and phenomena.