Phosphorescence

Part of speech: noun

Pronunciation: /ˌfɒs.fəˈɹɛs.əns/

Definitions

1. The emission of light by a substance after it has absorbed energy, with the light persisting for a noticeable duration after the energy source is removed
2. The property of emitting visible light after absorbing radiation, with the glow continuing for an extended period after the exciting energy ceases
3. A luminous phenomenon where substances release stored light energy gradually over time following exposure to an external energy source

Etymology: Phosphorescence takes its name from the element phosphorus, which was itself named for light. The Greek "phosphoros" meant "light-bearing," a name the ancients gave to the morning star, and when the element was isolated in the 1670s its glowing in the dark (it gives off a faint light as it slowly oxidises) prompted the name. The glow of phosphorus is actually chemiluminescence, a chemical reaction rather than the delayed re-emission that defines phosphorescence proper, so the modern term was built on a mistaken association. The word itself is a later formation. "Phosphorescent" was formed from "phosphorus" with the suffix "-escent," meaning "becoming or beginning to be," and "phosphoresce" was then backformed from it. Adding "-ence" to that verb gave the noun, which describes the quality or state of glowing after exposure to light or other energy has ended.

Synonyms: luminescence, glow, radiance, fluorescence, shine