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
source: WordNet 3.0
a cavity or passage in a tubular organ
The lumen of the intestine.
source: WordNet 3.0
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.