Which to use
“flue” is a noun and “fou” is an adjective - they look or sound alike but fill different roles in a sentence.
- #38,401
- “flue” frequency rank
- #48,244
- “fou” frequency rank
- 86645
- confusion score
Side-by-Side Comparison
| Feature | flue | fou |
|---|---|---|
| Definition | A pipe or duct that carries gaseous combustion products away from the point of combustion (such as a furnace). | Drunk. |
Letter map: flue vs fou
Shared letters muted; letters that set flue and fou apart highlighted. Shared run: 2. flue runs 4 letters (CCVV) against fou's 3 (CVV) - the length gap alone is often enough to separate them once you know to check it.
Part-of-speech tell for flue / fou
Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: flue is anoun and fouanadjective. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 86645, 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/. fou is at rank #48,244, tagged as anadj.
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 86645, this pair ranks #8,691 of 530,003 scored English confusable pairs - among the most confusable pairs.
Orthographic DNA of flue vs fou
Shared letters: fu. Private to "flue": el. Private to "fou": o.
"flue" · 4 letters · shape CCVV · "fou" · 3 letters · shape CVV
Known mistypes of this pair
- flue ← fflue · fleu · fllue · lfue
Frequently Asked Questions
Do "flue" and "fou" mean the same thing in a sentence?
In ordinary English text, does "flue" or "fou" show up more?
What to do next
Done with this confusable. These links stay specific to "flue" and "fou".
- Full dictionary entry for "flue" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "fou" - compare definitions side by side with the headword page. Word entry
- This pair ranks #8,691 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "flue" and "fou" also get mixed up with nearby pairs, the highest-scored neighbour is "FOMO 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 #8,691 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.