LUMENS

n. unit for measuring the rate at which light is transmitted (Optics); cavity, hollow space (Anatomy, Botany)

The lumen (symbol: lm) is the SI unit of luminous flux, a measure of the perceived power of light. Luminous flux differs from radiant flux, the measure of the total power of light emitted, in that luminous flux is adjusted to reflect the varying sensitivity of the human eye to different wavelengths of light.
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Noun
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
(synonym) lm
(hypernym) luminous flux unit
2. a cavity or passage in a tubular organ; "the lumen of the intestine"
(hypernym) cavity, bodily cavity, cavum

n. lumen, unit for measuring the rate at which light is transmitted (Optics); cavity, hollow space (Anatomy, Botany)

n. lumen, cavity