illuminance

[ ih-loo-muh-nuh ns ]
/ ɪˈlu mə nəns /

noun Optics.

Origin of illuminance

First recorded in 1940–45; illumin(ate) + -ance
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for illuminance

illuminance
/ (ɪˈluːmɪnəns) /

noun

the luminous flux incident on unit area of a surface. It is measured in luxSymbol: E v Sometimes called: illumination Compare irradiance
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Science definitions for illuminance

illuminance
[ ĭ-lōōmə-nəns ]

The luminous flux per unit area at any point on a surface exposed to incident light. It is measured in luxes. Also called illumination
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.