lumen

• POS: Noun
• HYPHEN: lu=men

CIDE DICTIONARY

lumen, n. [L., light, an opening for light.].

•  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.  [Webster 1913 Suppl.]
•  An opening, space, or cavity, esp. a tubular cavity; a vacuole.  [Webster 1913 Suppl.]

OXFORD DICTIONARY

lumen, n.
1 Physics the SI unit of luminous flux, equal to the amount of light emitted per second in a unit solid angle of one steradian from a uniform source of one candela.

Usage

Abbr.: lm.
2 Anat. (pl. lumina) a cavity within a tube, cell, etc.

Derivative

luminal adj.

Etymology

L lumen luminis a light, an opening

THESAURUS

lumen

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