DICT.TW Dictionary Taiwan
Lu·men n.; pl. L. Lumina E. Lumens .
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.
2. Biol. An opening, space, or cavity, esp. a tubular cavity; a vacuole.
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lumen
n 1: 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: lm]
2: a cavity or passage in a tubular organ; "the lumen of the
intestine"
[also: lumina (pl)]