lumen
1. svetlina, lumen
a cavity or passage in a tubular organ [votlina ali prehod v cevastem organu]
2. svetlina, lumen
a unit of luminous flux equal to the amount of light given out through a solid angle of 1 steradian by a point source of 1 candela intensity radiating uniformly in all directions [enota svetilnega pretoka, enaka svetlobnemu toku, oddanemu skozi trdninski kot 1 steradian, pri čemer vir oddaja svetlobo enakomerno v vse smeri z intenzivnostjo 1 kandele]