/ˈluːmən/, /ˈlumən/
OriginBorrowed from Latin lūmen (“light, an opening”). Use as a unit was first adopted by French physicist André Blondel in 1894.
- In the International System of Units, the derived unit of luminous flux; the light that is emitted in a solid angle of one steradian from a source of one candela. Symbol: lm.
- The cavity or channel within a tube or tubular organ.
- The cavity bounded by a plant cell wall.
- The bore of a tube such as a hollow needle or catheter.
Formslumens(plural) · lumina(plural)
Source: Wiktionary