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

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

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

IgA and other antibodies are secreted into the intestinal lumen.

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