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 Alpenglow Mini has four lighting modes that shine as bright as 150 lumens. Katrina Cossey, Parents, 9 May 2024 For instance, in 2007, the Energy Independence and Security Act set a lumens per watt standard for light bulbs that effectively banned the incandescent-type bulb. IEEE Spectrum, 10 Feb. 2024 The color-changing smart bulbs work with all major smart home platforms and light up homes with 1,100 lumens of brightness. Sheena Vasani, The Verge, 2 Apr. 2024 At 14,000 lumens per panel, at 100% the Skylight will starkly light every corner of your space. Anthony Karcz, Forbes, 29 Mar. 2024 Frequently Asked Questions How many lumens are recommended for outdoor use? Camryn Rabideau, Peoplemag, 19 Jan. 2024 Fluorescent light bulbs are next The Department of Energy proposed a rule in December 2022 that would require minimum lighting efficiency for fluorescent lights from 120 lumens per watt -- more than double the current requirements. Julia Jacobo, ABC News, 1 Aug. 2023 According to Atwell, most options feature multiple lumens settings, with the higher end being somewhere between 1,000 to 3,000 lumens, as seen with options like the Stanley Fatmax SL10LEDS Rechargeable Spotlight or the Nitecore EDC27 Ultra Slim Flashlight. Jack Byram, Better Homes & Gardens, 31 Mar. 2024 For reference, a standard 60-watt light bulb gives off about 800 lumens. Pamela Porter, Better Homes & Gardens, 21 Mar. 2024

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 May. 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

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