n., pl., -mens, or -mi·na (-mə-nə).
- Anatomy. The inner open space or cavity of a tubular organ, as of a blood vessel or an intestine.
- (Abbr. lm) Physics. The unit of luminous flux in the International System, equal to the amount of light given out through a solid angle by a source of one candela intensity radiating equally in all directions.
- Botany. The cavity bounded by a plant cell wall.
[Latin lūmen, an opening, light.]
lumenal lu'men·al or lu'min·al adj.
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
