Lumens

1 definition found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  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.
            [Webster 1913 Suppl.]
  
     2. (Biol.) An opening, space, or cavity, esp. a tubular
        cavity; a vacuole.
        [Webster 1913 Suppl.]