- 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. 2018
Examples from the Web for lumen
That reminds me, I'd better arrange a debate on immigration for the Lumen.
"She made a splendid impression on the Lumen," Colburn went on.
If the lumen of the tube is as fine as a hair, a considerable rise can be observed.Natural Philosophy
Just one more word, Lumen, before we conclude this interview.
Dear Lumen, I do not half understand this new effect of the laws of light.
- 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
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.)).
Online Etymology Dictionary, © 2010 Douglas Harper
- 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.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
- 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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.