# lumen

> English word · Noun · IPA /ˈluːmən/ · frequency rank #25,829

## Definitions
1. 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.
2. The cavity or channel within a tube or tubular organ.
3. The cavity bounded by a plant cell wall.
4. The bore of a tube such as a hollow needle or catheter.

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

## Easily confused with
- **lun** (https://plainspell.com/en/vs/lumen-vs-lun)
- **lump** (https://plainspell.com/en/vs/lumen-vs-lump)
- **lure** (https://plainspell.com/en/vs/lumen-vs-lure)
- **Lyme** (https://plainspell.com/en/vs/lumen-vs-lyme)
- **luxe** (https://plainspell.com/en/vs/lumen-vs-luxe)
- **Lupe** (https://plainspell.com/en/vs/lumen-vs-lupe)
- **lute** (https://plainspell.com/en/vs/lumen-vs-lute)
- **lumps** (https://plainspell.com/en/vs/lumen-vs-lumps)
- **Luton** (https://plainspell.com/en/vs/lumen-vs-luton)
- **Lyman** (https://plainspell.com/en/vs/lumen-vs-lyman)
- **lumia** (https://plainspell.com/en/vs/lumen-vs-lumia)
- **lupin** (https://plainspell.com/en/vs/lumen-vs-lupin)
- **lumpy** (https://plainspell.com/en/vs/lumen-vs-lumpy)
- **Luzon** (https://plainspell.com/en/vs/lumen-vs-luzon)
- **Lumley** (https://plainspell.com/en/vs/lumen-vs-lumley)
- **Len** (https://plainspell.com/en/vs/len-vs-lumen)
- **lum** (https://plainspell.com/en/vs/lum-vs-lumen)
- **Luke** (https://plainspell.com/en/vs/luke-vs-lumen)
- **lame** (https://plainspell.com/en/vs/lame-vs-lumen)
- **lime** (https://plainspell.com/en/vs/lime-vs-lumen)

## Common misspellings (7)
`llumen`, `lmuen`, `luemn`, `lumenn`, `lummen`, `lumne`, `ulmen`

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/lumen