Photometry

Part of speech: noun

Definitions

1. The field dedicated to measuring light and its luminous properties encompasses assessing intensity, brightness, and the distribution of light rays
2. This discipline involves the scientific evaluation of light intensity and its various characteristics, including luminous flux and illumination levels
3. The scientific study and quantification of visible light intensity and brightness from sources or reflected surfaces

Etymology: "Photometry" is a compound built from two Greek elements: "phōs" (genitive "phōtos"), meaning light, and "metron", meaning measure. The "-metry" ending, from "metron", is the same element that appears in "geometry" and "thermometry", where it signals an act or system of measurement. Put together, the word names the measuring of light. The result is a plain technical coinage rather than an old word that drifted in meaning. Its first element, "photo-", is the combining form of "phōs" that also gives "photograph" and "photosynthesis", so the word shares its opening with a whole family of light-related terms. Its second half links it to a long line of measurement words, all built on the same Greek root.