lumen

[loo-muh n]

noun, plural lu·mens, lu·mi·na [loo-muh-nuh] /ˈlu mə nə/.

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. Abbreviation: lm

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

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

Origin of lumen

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

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for lumen

Historical Examples of lumen

That reminds me, I'd better arrange a debate on immigration for the Lumen.
Ramsey Milholland
Booth Tarkington
"She made a splendid impression on the Lumen," Colburn went on.
Ramsey Milholland
Booth Tarkington
If the lumen of the tube is as fine as a hair, a considerable rise can be observed.
Natural Philosophy
Wilhelm Ostwald
Just one more word, Lumen, before we conclude this interview.
Lumen
Camille Flammarion
Dear Lumen, I do not half understand this new effect of the laws of light.
Lumen
Camille Flammarion

British Dictionary definitions for lumen

lumen

noun plural -mens or -mina (-mɪnə)

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 candelaSymbol: lm

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

a cavity within a plant cell enclosed by the cell walls

Derived Formslumenal or luminal, adjective

Word Origin for lumen

C19: New Latin, from Latin: light, aperture

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for lumen

unit of luminosity, 1897, coined 1894 by French physicist André-Eugène Blondel (1863-1938) from Latin lumen "light," related to lucere "to shine" (see light (n.)).

lumen in Medicine

lumen

[lōō′mən]

n. pl. lumens

The inner open space or cavity of a tubular organ, as of a blood vessel.

The unit of luminous flux in the International System of Units, equal to the amount of light given out through a solid angle by a source of one candela intensity radiating equally in all directions.

Related formslu′men•al null adj.

lumen in Science

lumen

[lōō′mən]

Plural lumens lumina

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

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.