lumen

noun
lu·​men | \ ˈlü-mən How to pronounce lumen (audio) \
plural lumens also lumina\ ˈlü-​mə-​nə How to pronounce lumina (audio) \

Definition of lumen

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

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Other Words from lumen

luminal or less commonly lumenal \ ˈlü-​mə-​nᵊl How to pronounce lumenal (audio) \ adjective

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 Epson Home Cinema 3800 plays HDR video at full 4K resolution, has a contrast ratio of 200,000:1, and provides a brightness of 3,000 lumens. Wired Staff, Wired, "14 Best Weekend Deals on Tablets, Smartwatches, and More," 6 June 2020 But the discovery of the serotonin in the gut lumen called the brain-only assumption into question. Natalie Meade, Quartz, "The key to good mental health in quarantine is in the food you eat," 24 Apr. 2020 If the city went out and just swapped lumens for the cheapest LED products out there, the astronomers would have marched on city hall with pitchforks and (night-vision-preserving) torches. Scott K. Johnson, Ars Technica, "How Flagstaff, Arizona, switched to LEDs without giving astronomers a headache," 22 Oct. 2019 For less than 9 ounces, this lantern has 225 lumens and will charge your smart phone in about 3.5 hours. Outdoor Life, "Outdoor lights for all your nighttime needs," 23 Apr. 2020 The low setting, at 50 lumens, is enough white light for camp tasks and trail-finding for 3.5 hours. T. Edward Nickens, Field & Stream, "The Best New Camping Gear of the Year," 7 Apr. 2020 The Pro model puts out an impressive 150 lumens of light and lasts 50 hours per charge. Outdoor Life, "Four Essential, Space-Saving Pieces of Camping Gear," 6 Apr. 2020 Lumens: Measuring the brightness of a bulb, lumens are usually around 800 for the average 60-watt old-fashioned incandescent. Gabrielle Hondorp, Popular Mechanics, "The 8 Best Smart Lights and Systems For Your Home," 12 Mar. 2020 Watts: All lightbulbs consume power, but smart lights are generally more economical—using only around 8-10 watts for about 800 lumens. Gabrielle Hondorp, Popular Mechanics, "The 8 Best Smart Lights and Systems For Your Home," 12 Mar. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'lumen.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of lumen

1873, in the meaning defined at sense 1

History and Etymology for lumen

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

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Time Traveler for lumen

Time Traveler

The first known use of lumen was in 1873

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Statistics for lumen

Last Updated

9 Jun 2020

Cite this Entry

“Lumen.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/lumen. Accessed 11 Jul. 2020.

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More Definitions for lumen

lumen

noun
lu·​men | \ ˈlü-mən How to pronounce lumen (audio) \
plural lumina\ -​mə-​nə How to pronounce lumina (audio) \ or lumens

Medical Definition of lumen

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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More from Merriam-Webster on lumen

Rhyming Dictionary: Words that rhyme with lumen

Britannica English: Translation of lumen for Arabic Speakers

Britannica.com: Encyclopedia article about lumen

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