Photometria

Part of speech: noun

Definitions

1. A branch of science that deals with the measurement of light and its properties
2. The study involving the quantitative assessment of brightness and illumination in various contexts
3. A discipline focused on evaluating visible radiation and its effects on visual performance and light perception

Etymology: Johann Heinrich Lambert, the Swiss-German mathematician and physicist, used "photometria" as the title of his treatise on measuring light, and the term stuck as the name for the discipline. The word is built from two Greek elements: "phōs," meaning light, and "metron," meaning measure. The same pairing gives English "photograph," "photon," and "photometer," but "photometria" names the whole field rather than an instrument or an image. Its modern scope has widened from measuring light alone to include how visible radiation affects seeing and perception.

Synonyms: photometry, light measurement, radiometry