LUMENS
Noun
lumens
plural of lumen
Source: Wiktionary
LUMEN
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