'Lumen' definitions:

Definition of 'lumen'

From: WordNet
noun
A unit of luminous flux equal to the amount of light given out through a solid angle of 1 steradian by a point source of 1 candela intensity radiating uniformly in all directions [syn: lumen, lm]
noun
A cavity or passage in a tubular organ; "the lumen of the intestine"

Definition of 'Lumen'

From: GCIDE
  • Lumen \Lu"men\, n.; pl. L. Lumina, E. Lumens. [L., light, an opening for light.]
  • 1. (Photom.) (a) A unit of illumination, being the amount of illumination of a unit area of spherical surface, due to a light of unit intensity placed at the center of the sphere. (b) A unit of light flux, being the flux through one square meter of surface the illumination of which is uniform and of unit brightness. [Webster 1913 Suppl.]
  • 2. (Biol.) An opening, space, or cavity, esp. a tubular cavity; a vacuole. [Webster 1913 Suppl.]

Synonyms of 'lumen'

From: Moby Thesaurus

Words containing 'Lumen'