from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. The unit of brightness in the centimeter-gram-second system, equivalent to the brightness of a perfectly diffusing surface that emits or reflects one lumen per square centimeter.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. a cgs unit of illumination; the brightness of a surface that emits one lumen per square centimetre


After Johann Heinrich Lambert (1728-1777), German physicist and astronomer.
(American Heritage® Dictionary of the English Language, Fourth Edition)



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