lumen

[ loo-muhn ]

noun

, plural lu·mens, lu·mi·na [loo, -m, uh, -n, uh].

1. Optics. the unit of luminous flux, equal to the luminous flux emitted in a unit solid angle by a point source of one candle intensity. : lm
2. Anatomy. the canal, duct, or cavity of a tubular organ.
3. Botany. (of a cell) the cavity that the cell walls enclose.

lumen

/ ˈluːmɪn /

noun

1. the derived SI unit of luminous flux; the flux emitted in a solid angle of 1 steradian by a point source having a uniform intensity of 1 candela lm
2. anatomy a passage, duct, or cavity in a tubular organ
3. a cavity within a plant cell enclosed by the cell walls

lumen

/ lo̅o̅′mən /

, Plural lumens

1. The central space within a tube-shaped body part or organ, such as a blood vessel or the intestine.
2. The SI derived unit used to measure the amount of light passing through a given area per second. One lumen is equal to the luminous flux passing per unit solid angle from a light source with a strength of one candela.

Derived Forms

• ˈlumenal, adjective

Word History and Origins

Origin of lumen¹

1870–75; < New Latin, special uses of Latin lūmen (stem lūmin- ) light, window

Word History and Origins

Origin of lumen¹

C19: New Latin, from Latin: light, aperture

Example Sentences

While most kitchen lighting is built in, it’s possible to bring a few extra lumens to dark corners, and an extra dash of style, with plug-in lamps.

From Seattle Times

Instead of being eliminated to the lumen, they infiltrate into the tissue, producing high-grade cancer cells.

From Science Daily

Most incandescent bulbs can only create about 15 lumens with 1 watt, so they don’t meet the guidelines.

From NewsForKids.net

“If you break it down bio meaning life and lumen meaning light and so bioluminescence is really the all-encompassing term that refers to life that gives off light,” said Rouches.

From Seattle Times

The new efficiency standard announced by the Biden administration requires light bulbs to meet a minimum standard of producing 45 lumens per watt.

From New York Times