candela

IPA/kænˈdiːlə/
KK[kˌændˈɛlə]IPA/kænˈdiːlə/

candela — noun

  • candelasingular
  • candelasplural

1. the SI base unit used to measure how bright a light source appears from a specif

1.nounB2
Definition

the SI base unit used to measure how bright a light source appears from a specific direction

Example

The new desk lamp produces 12 candelas, giving Elena enough light to read comfortably.

produces + [number] candelas

A standard candle flame has a luminous intensity of roughly one candela.

one candela ≈ brightness of one candle

Common collocations
  • luminous intensity
  • measured in candelas
  • candela rating
  • candela output

Common Mistakes

This light bulb is 800 candela.
This light bulb has a luminous intensity of 800 candelas.
candela measures luminous intensity, not the bulb itself.

Word family

Synonym discussion

Sense: noun/1

Candela, lumen, lux, and watt all relate to light but measure different things. Candela (cd) measures luminous intensity — how bright a light source appears in a single direction — much like a candle flame has roughly 1 cd. Lumen (lm) measures total light output in all directions: a 60-watt bulb emits about 800 lm. Lux (lx) measures illuminance, or lumens per square metre — how much light hits a surface. Watt (W) measures electrical power, not visible light directly. So 1 candela = 1 lumen per steradian (a unit of solid angle), while 1 lux = 1 lumen per square metre. A learner buying bulbs would see lumens for brightness, but a lighting designer uses candelas for spotlights and laser pointers.

lumen ↗luxwatt ↗

Common collocations

Nouns

  • candela rating
  • candela output
  • candela value

Phrases

  • measured in candelas
  • expressed in candelas

Prepositions

  • in candelas
  • per candela

Etymology

LatinEnglish

Candela comes directly from the Latin word candēla, meaning 'candle'. The original definition of the unit was based on the light emitted by a standard candle made of spermaceti wax burning at a specific rate. In 1979, the definition was updated to the current physical constant based on monochromatic radiation, but the link to candlelight remains in the name.

First known use

1949

1949, in the meaning defined above