Which to use
“flex” and “flue” are a confusable English pair: similar on the page, but distinct in meaning, check the gloss before you choose.
- #10,696
- “flex” frequency rank
- #38,401
- “flue” frequency rank
- 49097
- confusion score
Side-by-Side Comparison
| Feature | flex | flue |
|---|---|---|
| Definition | Flexibility, pliancy. | A pipe or duct that carries gaseous combustion products away from the point of combustion (such as a furnace). |
Where the eye mixes flex and flue
Muted = shared; highlighted = the visual trap. They share 3 letters in sequence.
Why the eye confuses flex with flue
A purely visual mix-up. flex (/flɛks/) and flue (/fluː/) are said differently, so reading them aloud is the quickest way to catch the wrong one. On the page they stay close: they share most of their letters but differ in 2 positions. Our composite confusion score for this pair is 49097, derived from the frequency rank of both members and their visual similarity.
flex is recorded at frequency rank #10,696, classified as anoun, pronounced /flɛks/. flue is at rank #38,401, tagged as anoun, pronounced /fluː/.
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 49097, this pair ranks #186,874 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of flex vs flue
Shared letters: efl. Private to "flex": x. Private to "flue": u.
"flex" · 4 letters · shape CCVC · "flue" · 4 letters · shape CCVV
Known mistypes of this pair
Frequently Asked Questions
Can "flex" and "flue" be used interchangeably?
In ordinary English text, does "flex" or "flue" show up more?
Useful next steps
Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.
- Full dictionary entry for "flex" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "flue" - compare definitions side by side with the headword page. Word entry
- This pair ranks #186,874 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "flex" and "flue" 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 #186,874 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.