lumen
Americannoun
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lumens,
plural
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lumina
plural
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Optics. the unit of luminous flux, equal to the luminous flux emitted in a unit solid angle by a point source of one candle intensity. lm
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Anatomy. the canal, duct, or cavity of a tubular organ.
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Botany. (of a cell) the cavity that the cell walls enclose.
noun
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lm. the derived SI unit of luminous flux; the flux emitted in a solid angle of 1 steradian by a point source having a uniform intensity of 1 candela
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anatomy a passage, duct, or cavity in a tubular organ
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a cavity within a plant cell enclosed by the cell walls
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lumens
plural
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The central space within a tube-shaped body part or organ, such as a blood vessel or the intestine.
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The SI derived unit used to measure the amount of light passing through a given area per second. One lumen is equal to the luminous flux passing per unit solid angle from a light source with a strength of one candela.
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Etymology
Origin of lumen
1870–75; < New Latin, special uses of Latin lūmen (stem lūmin- ) light, window
Explanation
The lumen is a unit of measurement for the brightness of light. If a light bulb is blindingly bright, it produces a lot of lumens. The lumen is a basic unit for measuring brightness, just as the gram is a basic unit for measuring mass. A typical light bulb in your home might produce about 1000 lumens. Lumen is related to the word luminous, which means “bright” or “radiant.”
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Studies have reported that when activating mutants of "Ras" proteins are expressed in mammalian epithelial cells, they are pushed toward the lumen, excreted along with other bodily waste, and eliminated by competition.
From Science Daily ● Nov. 22, 2023
Activated Ras mutant epithelial cells, which would normally be eliminated into the lumen, instead infiltrated diffusely into the tissue to form highly invasive cancerous tumors.
From Science Daily ● Nov. 22, 2023
“If you break it down bio meaning life and lumen meaning light and so bioluminescence is really the all-encompassing term that refers to life that gives off light,” said Rouches.
From Seattle Times ● Aug. 28, 2023
Columnar epithelial cells absorb material from the lumen of the digestive tract to prepare the material for entry into the body.
From Textbooks ● Jun. 9, 2022
So we sat there for a couple hours talking to the screen together, navigating this invisible labyrinthine cave without a single lumen of light.
From "The Fault in Our Stars" by John Green
While most kitchen lighting is built in, it’s possible to bring a few extra lumens to dark corners, and an extra dash of style, with plug-in lamps.
From Seattle Times ● Jan. 8, 2024
In March, Cree LED announced white LEDs offering 228 lumens per watt.
From BBC ● Dec. 18, 2023
Most incandescent bulbs can only create about 15 lumens with 1 watt, so they don’t meet the guidelines.
From NewsForKids.net ● Aug. 17, 2023
As a critic, Gilman was brilliant; he made the light in your head brighten by a few lumens.
From New York Times ● Feb. 13, 2023
That is, if energy of this wave-length alone were radiated by a hypothetical light-source, each watt would produce 625 lumens.
From Artificial Light Its Influence upon Civilization by Matthew Luckiesh
The testes of specimens that were nearly mature contained primary and secondary spermatocytes but lacked lumina; it was thought that such individuals would have matured in the following summer and bred in the following autumn.
From Natural History of the Ornate Box Turtle, Terrapene ornata ornata Agassiz by John M. Legler
Strictural lumina are much more apt to be concentric as approached from below because there has been no distortion by pressure dilatation due to stagnation of the food operating through a long period of time.
From Bronchoscopy and Esophagoscopy A Manual of Peroral Endoscopy and Laryngeal Surgery by Chevalier Jackson
In Merulius lacrymans Hartig has observed thin-walled hyphae with large lumina, the septa of which are perforated like those of sieve-tubes.
From Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" by Various
Celsius and Linnæus were complimented with the title of lumina academiæ, on account of their great learning and reputation.
From Lives of Eminent Zoologists, from Aristotle to Linnæus with Introductory remarks on the Study of Natural History by William MacGillivray
Any agent which acts to produce thickening of the walls of the arterioles, narrowing their lumina, produces the same effect.
From Arteriosclerosis and Hypertension: with Chapters on Blood Pressure, 3rd Edition. by Louis Marshall Warfield
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