fluevsfunWhat's the difference?

Which to use

“flue” and “fun” are a confusable English pair: similar on the page, but distinct in meaning, check the gloss before you choose.

#38,401
“flue” frequency rank
#502
“fun” frequency rank
38903
confusion score

Side-by-Side Comparison

Feature flue fun
Definition A pipe or duct that carries gaseous combustion products away from the point of combustion (such as a furnace). Amusement, enjoyment or pleasure.

Where the eye mixes flue and fun

Muted = shared; highlighted = the visual trap. They share 2 letters in sequence.

4 ch
flue
3 ch
fun

Why the eye confuses flue with fun

A purely visual mix-up. flue (/fluː/) and fun (/fʌn/) are said differently, so reading them aloud is the quickest way to catch the wrong one. On the page they stay close: they differ by 1 letter(s) in length. Our composite confusion score for this pair is 38903, derived from the frequency rank of both members and their visual similarity.

flue is recorded at frequency rank #38,401, classified as anoun, pronounced /fluː/. fun is at rank #502, tagged as anoun, pronounced /fʌn/.

Glosses for this pair are partially populated in our dataset, but the full side-by-side definitions above should still guide you to the right choice.

With a confusion score of 38903, this pair ranks #281,664 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of flue vs fun

Shared letters: fu. Private to "flue": el. Private to "fun": n.

"flue" · 4 letters · shape CCVV  ·  "fun" · 3 letters · shape CVC

Known mistypes of this pair

  • fluefflue · fleu · fllue · lfue

Frequently Asked Questions

Do "flue" and "fun" mean the same thing in a sentence?
No. They are said differently (/fluː/ versus /fʌn/) and carry different meanings; reading the sentence aloud is usually enough to catch the wrong one.
Which is more common, "flue" or "fun"?
"fun" is the more common of the two: it sits at frequency rank #502 in our English list, against #38,401 for "flue". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

What to do next

Eye-level mix-up between "flue" and "fun" is sorted above. Next: full entries or other pairs that share a letter shape.

  • Full dictionary entry for "flue" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "fun" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #281,664 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "flue" and "fun" also get mixed up with nearby pairs, the highest-scored neighbour is "flue vs fou". Nearby pair
  • Recorded mistypes exist for at least one side of this pair, useful when a spell-checker or OCR lands on the wrong form. See mistypes

Confusion rank #281,664 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list