Stilb

Part of speech: noun

Definitions

1. A unit measuring luminance equal to one candela per square centimeter, quantifying the intensity of light emitted from a surface
2. A photometric term representing the brightness of a surface area, defined by a specific amount of luminous intensity per unit area
3. An expression of luminous intensity concentration per square centimeter, used to describe the level of light emitted or reflected from a surface area

Etymology: The unit of brightness called the stilb was coined around 1920 by the French physicist André Blondel, who needed a name for a photometric quantity that measured how bright a surface appears. He reached back to Ancient Greek "stílbō," meaning "I glitter" or "I shine," the same root that gives us words for things that give off a sparkle. The choice is fitting, since the unit describes luminance: a stilb is one candela per square centimetre, so the name points directly at a surface that gleams. Blondel's coinage belongs to the early twentieth century, when physicists were systematising measures of light and needed compact names for them.

Synonyms: unit of luminance