Lumen

[loo-muh n] /ˈlu mən/

noun, plural lumens, lumina
[loo-muh-nuh] /ˈlu mə nə/ (Show IPA)
1.
Optics. the unit of luminous flux, equal to the luminous flux emitted in a unit solid angle by a point source of one candle intensity.
Abbreviation: lm.
2.
Anatomy. the canal, duct, or cavity of a tubular organ.
3.
Botany. (of a cell) the cavity that the cell walls enclose.
/ˈluːmɪn/
noun (pl) -mens, -mina (-mɪnə)
1.
the derived SI unit of luminous flux; the flux emitted in a solid angle of 1 steradian by a point source having a uniform intensity of 1 candela lm
2.
(anatomy) a passage, duct, or cavity in a tubular organ
3.
a cavity within a plant cell enclosed by the cell walls
n.

unit of luminosity, 1897, coined 1894 by French physicist André-Eugène Blondel (1863-1938) from Latin lumen “light,” related to lucere “to shine” (see light (n.)).

lumen lu·men (lōō’mən)
n. pl. lumens or lu·mi·na (-mə-nə)

lu’men·al or lu’min·al adj.
lumen
(l’mən)
Plural lumens or lumina