lumen

noun

lu·​men ˈlü-mən How to pronounce lumen (audio)
plural lumens also lumina ˈlü-mə-nə How to pronounce lumen (audio)
1
: the cavity of a tubular organ or part
the lumen of a blood vessel
2
: the bore of a tube (as of a hollow needle or catheter)
3
: a unit of luminous flux equal to the light emitted in a unit solid angle by a uniform point source of one candle intensity
luminal adjective
or less commonly lumenal

Did you know?

There are two common units for measuring light, the candela and the lumen. Both are recognized as standard international units, which also include the second (for time), the kilogram (for weight), and the meter (for length). The candela is a measure of intensity; an ordinary candle gives off light with the intensity of about one candela. The lumen is a measure of "luminous flux;" a standard 100-watt lightbulb gives off 1500–1700 lumens. Luminous flux indicates how much light is actually perceived by the human eye. Technologies vary in how efficiently they turn electricity into light; halogen lights produce about 12 lumens per watt, ordinary incandescent lightbulbs produce about 15 lumens per watt, and compact fluorescent bulbs produce about 50 lumens per watt.

Examples of lumen in a Sentence

Recent Examples on the Web The new fixtures are expected to put out between 2,500 and 4,500 lumens of light, an MTA spokesman told the Daily News. Evan Simko-Bednarski, New York Daily News, 20 Feb. 2024 Each light gives off 80 lumens for a subtle yet safe illumination and is waterproof. Cristian Esteban, Rolling Stone, 21 June 2024 Typical florescent bulbs of the kind used by the MTA put out between 2,000 and 3,000 lumens. Evan Simko-Bednarski, New York Daily News, 20 Feb. 2024 This mini lantern also comes in 250 lumens and 500 lumens with several lighting modes and the same weather-resistant rating as the 150 option. Katrina Cossey, Parents, 9 May 2024 See all Example Sentences for lumen 

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'lumen.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

New Latin lumin-, lumen, from Latin, light, air shaft, opening

First Known Use

1873, in the meaning defined at sense 1

Time Traveler
The first known use of lumen was in 1873

Dictionary Entries Near lumen

Cite this Entry

“Lumen.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/lumen. Accessed 18 Jul. 2024.

Kids Definition

lumen

noun
lu·​men ˈlü-mən How to pronounce lumen (audio)
plural lumens also lumina -mə-nə How to pronounce lumen (audio)
: a unit of light quantity equal to the light on a unit surface all points of which are at a unit distance from a point source of light having a strength of one candle

Medical Definition

lumen

noun
lu·​men ˈlü-mən How to pronounce lumen (audio)
plural lumina -mə-nə How to pronounce lumen (audio) or lumens
1
: the cavity of a tubular organ or part
the lumen of a blood vessel
2
: the bore of a tube (as of a hollow needle or catheter)
3
: a unit of luminous flux equal to the light emitted in a steradian by a uniform point source of one candle intensity

More from Merriam-Webster on lumen

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