lumen

lu·men
L1U1M3E1N1
UK/ˈluːmən/US/ˈlumən/

noun

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.

Similar
lm
OriginLatin lūmen ← Proto-Italic *louksmən ← Proto-Indo-European *léwksmn̥ →
Less commonScrabble 7
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Meanings

nounlumen (plural lumens or lumina)

plural lumens · plural lumina

  1. natural sciencesIn 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.
  2. anatomyThe cavity or channel within a tube or tubular organ.
  3. biologyThe cavity bounded by a plant cell wall.
  4. medicineThe bore of a tube such as a hollow needle or catheter.

Synonyms & antonyms

nouna unit of luminous flux equal to the amount of light given out through a solid angle of 1 steradian by a point source of 1 candela intensity radiating uniformly in all directions

Similar
lm
Broader
luminous flux unit

Synonym sets from Open English WordNet, CC BY 4.0.

Origin

  1. Proto-Indo-European*lewk-
  2. Proto-Indo-European*léwksmn̥
  3. Proto-Italic*louksmən
  4. Latinlūmen
  5. Englishlumen

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

More words from Latin

Full word history & related roots →

Translations

Arabic لُومِن
  • لُومِن (lūmin)SI-unit for luminous flux
Chinese Mandarin 流明, 內腔 /内腔
  • 流明 (liúmíng)SI-unit for luminous flux
  • 內腔 /内腔 (nèiqiāng)anatomy: cavity within tubular organ
Czech lumen
  • lumenSI-unit for luminous flux
Finnish luumen, lumen
  • luumenSI-unit for luminous flux
  • lumenanatomy: cavity within tubular organ
  • onteloanatomy: cavity within tubular organ
  • lumenbotany: cavity bounded by cell wall
  • ontelobotany: cavity bounded by cell wall
  • lumenmedicine: bore of a tube
French lumen
  • lumenSI-unit for luminous flux
German Lumen
  • LumenSI-unit for luminous flux
Greek λούμεν
  • λούμεν (loúmen)SI-unit for luminous flux
Hebrew נהור
  • נהור (n'hor)anatomy: cavity within tubular organ
Indonesian lumen
  • lumenSI-unit for luminous flux
Japanese ルーメン, 内腔
  • ルーメン (rūmen)SI-unit for luminous flux
  • 内腔 (naikū)anatomy: cavity within tubular organ
Korean 루멘, 내강
  • 루멘 (rumen)SI-unit for luminous flux
  • 내강 (naegang)anatomy: cavity within tubular organ
Malay lumen
  • lumenSI-unit for luminous flux
Polish lumen
  • lumenSI-unit for luminous flux
Portuguese lúmen, lúmen
  • lúmenSI-unit for luminous flux
  • lúmenanatomy: cavity within tubular organ
Romanian lumen, lumen
  • lumenSI-unit for luminous flux
  • lumenanatomy: cavity within tubular organ
  • lumenbotany: cavity bounded by cell wall
Russian лю́мен, по́лость
  • лю́мен (ljúmen)SI-unit for luminous flux
  • по́лость (pólostʹ)botany: cavity bounded by cell wall
Swedish lumen
  • lumenSI-unit for luminous flux
Tagalog lumen
  • lumenSI-unit for luminous flux
Thai ลูเมน
  • ลูเมน (luu-men)SI-unit for luminous flux

Rhymes & wordplay

Rhymes with lumen

humanNewmaninhumanbitumenrumencrewmannumencerumenalterhumanchuman
All rhymes →

Anagrams

Melun
Cite this entry
APA

lumen. (n.d.). In WatkinsX Dictionary. Retrieved November 3, 2026, from https://dictionary.watkinsx.com/word/lumen

MLA

“lumen.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/lumen. Accessed November 3, 2026.

Chicago

WatkinsX Dictionary, s.v. “lumen,” accessed November 3, 2026, https://dictionary.watkinsx.com/word/lumen.

Source: lumen on Wiktionary, CC BY-SA 4.0.