lumen

play
noun lu·men \ˈlü-mən\

Definition of lumen

plural

lumens

also

lumina

play \ˈlü-mə-nə\
  1. 1 :  the cavity of a tubular organ or part the lumen of a blood vessel

  2. 2 :  the bore of a tube (as of a hollow needle or catheter)

  3. 3 :  a unit of luminous flux equal to the light emitted in a unit solid angle by a uniform point source of one candle intensity

luminal

or less commonly

lumenal

play \ˈlü-mə-nəl\ adjective

Recent Examples of lumen from the Web

  • The blinding 2,800 lumens present images of the items at 1,024 x 768pixels (shown above), a resolution that matches the best data projectors, but its video inputs allow for only standard – not hi-def – sources.

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'lumen'. Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Did You Know?

There are two common units for measuring light, the candela and the lumen. Both are recognized as standard international units, which also include the second (for time), the kilogram (for weight), and the meter (for length). The candela is a measure of intensity; an ordinary candle gives off light with the intensity of about one candela. The lumen is a measure of "luminous flux;" a standard 100-watt lightbulb gives off 1500–1700 lumens. Luminous flux indicates how much light is actually perceived by the human eye. Technologies vary in how efficiently they turn electricity into light; halogen lights produce about 12 lumens per watt, ordinary incandescent lightbulbs produce about 15 lumens per watt, and compact fluorescent bulbs produce about 50 lumens per watt.

Origin and Etymology of lumen

New Latin lumin-, lumen, from Latin, light, air shaft, opening


First Known Use: 1873


Medical Dictionary

lumen

play
noun lu·men \ˈlü-mən\

Medical Definition of lumen

plural

lumina

\-mə-nə\play or

lumens

  1. 1:  the cavity of a tubular organ or part the lumen of a blood vessel

  2. 2:  the bore of a tube (as of a hollow needle or catheter)

  3. 3:  a unit of luminous flux equal to the light emitted in a steradian by a uniform point source of one candle intensity


Learn More about lumen


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