lumen
lu·men
noun \ˈlü-mən\ plural lumens also lu·mi·na\-mə-nə\
Definition of LUMEN
1
: the cavity of a tubular organ or part <the lumen of a blood vessel>
2
: the bore of a tube (as of a hollow needle or catheter)
3
: a unit of luminous flux equal to the light emitted in a unit solid angle by a uniform point source of one candle intensity
— lu·mi·nal also lu·men·al \-mə-nəl\ adjective
See Origin of LUMEN
New Latin lumin-, lumen, from Latin, light, air shaft, opening
First Known Use: 1873
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