Which to use
“foo” is a noun and “fou” is an adjective - they look or sound alike but fill different roles in a sentence.
- #43,447
- “foo” frequency rank
- #1,063
- “fou” frequency rank
- 44510
- confusion score
Side-by-Side Comparison
| Feature | foo | fou |
|---|---|---|
| Definition | Variable métasyntaxique en programmation informatique. | Qualifie une personne qui a perdu la raison, qui est atteinte d’aliénation mentale. |
Same sound, different letters: foo vs fou
Muted letters are shared; highlighted letters are the only spelling cue when pronunciation matches. Shared run: 2 letters.
Homophone desk: foo vs fou
Say them out loud and nothing separates them: foo and fou carry the same recorded pronunciation, \fu\. Grammar is what tells them apart: one is anoun, the other anadjective, so most sentences will only accept one of them. They differ by a single letter - o in “foo” becomes u in “fou”. Our composite confusion score for this pair is 44510, derived from the frequency rank of both members and their visual similarity.
foo is recorded at frequency rank #43,447, classified as anoun, pronounced \fu\. fou is at rank #1,063, tagged as anadj, pronounced \fu\.
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 44510, this pair ranks #209,945 of 440,172 scored French confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of foo vs fou
Shared letters: fo. Private to "foo": -. Private to "fou": u.
"foo" · 3 letters · shape CVV · "fou" · 3 letters · shape CVV
Frequently Asked Questions
Can "foo" and "fou" be used interchangeably?
Which is more common, "foo" or "fou"?
After this comparison
Sound matches; spelling doesn't. Use the exits below to lock the right form or check a cousin pair.
- Full dictionary entry for "foo" 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 #209,945 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
- "foo" and "fou" also get mixed up with nearby pairs, the highest-scored neighbour is "Fee vs foo". Nearby pair
Confusion rank #209,945 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.