# flue

> English word · Noun · IPA /fluː/ · frequency rank #38,401

## Definitions
1. A pipe or duct that carries gaseous combustion products away from the point of combustion (such as a furnace).
2. An enclosed passageway in which to direct a current of air or other gases along.
3. A woolly or downy substance; down, nap; a piece of this.
4. In an organ flue pipe, the opening between the lower lip and the languet.

## Etymology
From Middle English flue, flewe (“mouthpiece of a hunting horn”), of uncertain origin. Perhaps a back-formation from Middle English *flews (mistaken as a plural), from Old English flēwsa (“a flow, flowing, flux”). Alternatively, perhaps an alteration of Middle English floute, fleute, flote (“a pipe”), see English flute. Compare also Middle Dutch vloegh (“groove, channel, flute of a fluted column”).

## Easily confused with
- **fu** (https://plainspell.com/en/vs/flue-vs-fu)
- **fun** (https://plainspell.com/en/vs/flue-vs-fun)
- **fly** (https://plainspell.com/en/vs/flue-vs-fly)
- **fur** (https://plainspell.com/en/vs/flue-vs-fur)
- **foe** (https://plainspell.com/en/vs/flue-vs-foe)
- **FTE** (https://plainspell.com/en/vs/flue-vs-fte)
- **fut** (https://plainspell.com/en/vs/flue-vs-fut)
- **fou** (https://plainspell.com/en/vs/flue-vs-fou)
- **free** (https://plainspell.com/en/vs/flue-vs-free)
- **four** (https://plainspell.com/en/vs/flue-vs-four)
- **fuel** (https://plainspell.com/en/vs/flue-vs-fuel)
- **foul** (https://plainspell.com/en/vs/flue-vs-foul)
- **fuse** (https://plainspell.com/en/vs/flue-vs-fuse)
- **flux** (https://plainspell.com/en/vs/flue-vs-flux)
- **FTSE** (https://plainspell.com/en/vs/flue-vs-ftse)
- **foie** (https://plainspell.com/en/vs/flue-vs-foie)
- **fume** (https://plainspell.com/en/vs/flue-vs-fume)
- **fluid** (https://plainspell.com/en/vs/flue-vs-fluid)
- **flush** (https://plainspell.com/en/vs/flue-vs-flush)
- **flyer** (https://plainspell.com/en/vs/flue-vs-flyer)

## Common misspellings (4)
`fflue`, `fleu`, `fllue`, `lfue`

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