lumen
(noun) a cavity or passage in a tubular organ; “the lumen of the intestine”
lumen, lm
(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
Source: WordNet® 3.1
lumen (plural lumens or lumina)
(physics) In the International System of Units, the derived unit of luminous flux; the light that is emitted in a solid angle of one steradian from a source of one candela. Symbol: lm.
(anatomy) The cavity or channel within a tube or tubular organ.
(botany) The cavity bounded by a plant cell wall.
(medicine) The bore of a tube such as a hollow needle or catheter.
Source: Wiktionary
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.
2. (Biol.) An opening, space, or cavity, esp. a tubular cavity; a vacuole.
Source: Webster’s Unabridged Dictionary 1913 Edition
19 June 2025
(noun) the condition of belonging to a particular place or group by virtue of social or ethnic or cultural lineage; “his roots in Texas go back a long way”; “he went back to Sweden to search for his roots”; “his music has African roots”
Decaffeinated coffee is not caffeine-free. Studies from the National Institute of Health (US) have shown that virtually all decaf coffee types contain caffeine. A 236-ml (8-oz) cup of decaf coffee contains up to 7 mg of caffeine, whereas a regular cup provided 70-140 mg.
