lumen

American  

[loo-muhn] / ˈlu mən /

noun

plural

lumens, lumina

1. 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

2. Anatomy. the canal, duct, or cavity of a tubular organ.

3. Botany. (of a cell) the cavity that the cell walls enclose.

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lumen British  

/ ˈluːmɪn /

noun

1.  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

2. anatomy a passage, duct, or cavity in a tubular organ

3. a cavity within a plant cell enclosed by the cell walls

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lumen Scientific  

/ lo̅o̅′mən /

plural

lumens

1. The central space within a tube-shaped body part or organ, such as a blood vessel or the intestine.

2. 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.

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Other Word Forms

• lumenal adjective

Etymology

Origin of lumen

1870–75; < New Latin, special uses of Latin lūmen (stem lūmin- ) light, window

Example Sentences

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

Instead of being eliminated to the lumen, they infiltrate into the tissue, producing high-grade cancer cells.

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

Na+ and/or K+ ions are actively transported into the lumen of the tubules.

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