ENGLISH
REFERENCE

lumen

n. countable
C2 Proficiency US //ˈɫumən// UK //lˈuːmɛn// lu·men

n. a unit that measures the total amount of light coming from a source like a bulb. The higher the number, the brighter the light looks to your eyes.

n. the SI unit of luminous flux, equal to the amount of light emitted per second in a unit solid angle of one steradian from a uniform source of one candela.


SIMPLE

This LED bulb produces 800 lumens of light.

CONTEXTUAL

When shopping for energy-efficient lighting, consumers should compare lumens to determine brightness rather than relying on wattage.

COMPLEX

The architectural lighting plan specified a minimum of five hundred lumens per square metre to ensure the workspace remained functional during the winter months when natural light is scarce.

Synonyms
Usage

Commonly used in the plural when describing the output of lamps or digital projectors.

Pitfall

This bulb has 60 watts of brightnessThis bulb has 800 lumens of brightnessWatts measure power consumption, while lumens measure the actual light output or brightness.

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