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

Keep scrolling for more

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 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 Nassi's team used several $200-$300 projectors successfully, one of which was rated for only 854x480 resolution and 100 lumens. Ars Technica, "How a $300 projector can fool Tesla’s Autopilot," 28 Jan. 2020 There are eight programmable color zones on each strip and 700 lumens per strip. Billy Cadden, Popular Science, "The best LED light strips," 6 Feb. 2020 This little device is used to help detect lumens per square meter, also known as the intensity of light. Popular Science, "Six must-haves for lovers of houseplants," 27 Sep. 2019 Each rechargeable unit can illuminate the night for up to 40 hours on the low setting, the headband is a moisture-wicking fabric that doesn't slide around on sweaty foreheads, and the LED bulbs put out 330 lumens of light. Ben Romans, Field & Stream, "Great Survival Gift Ideas for 2019," 22 Nov. 2019 With the passage of energy legislation in 2007, the Department of Energy required that most general-service lightbulbs emit at a minimum efficiency of 45 lumens per watt by the beginning of 2020. Laura Reiley, Washington Post, "Indoor farming is one of the decade’s hottest trends, but regulations make success elusive," 19 Nov. 2019 For comparison, the typical home theater projection system is between 3,000 and 4,000 lumens, said Dodd Technologies president Mark Dodd. Domenica Bongiovanni, Indianapolis Star, "Major video and light displays will soon start at Monument Circle. Here's what you'll see.," 17 May 2019

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.

See More

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

Keep scrolling for more

Learn More about lumen

Time Traveler for lumen

Time Traveler

The first known use of lumen was in 1873

See more words from the same year

Statistics for lumen

Last Updated

31 Mar 2020

Cite this Entry

“Lumen.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/lumen. Accessed 3 Apr. 2020.

Keep scrolling for more

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

Keep scrolling for more

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

Comments on lumen

What made you want to look up lumen? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

See Definitions and Examples »

Get Word of the Day daily email!

Test Your Vocabulary

Name that Thing: Flower Edition

Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Syn City

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!