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.
Frequency
Pronounced as (IPA)
/ˈluːmən/
Etymology
Borrowed from Latin lūmen (“light, an opening”). Use as a unit was first adopted by French physicist André Blondel in 1894.