LUMEN
- the inner passage of a tubular organ [n LUMENS, LUMINA] : LUMENAL [adj], LUMINAL [adj]
- the cavity of a tubular organ or part the lumen of a blood vessel
- unit of luminous flux equal to the light emitted in a unit solid angle by a uniform point source of one candle intensity
- the unit of luminous flux, equal to the luminous flux emitted in a unit solid angle by a point source of one candle intensity
- the canal, duct, or cavity of a tubular organ
- (of a cell) the cavity that the cell walls enclose