fiovsfoiWhat's the difference?

Quick tell: fio is a noun, foi is a verb, so they fill different roles in a sentence.

Which to use

“fio” is a noun and “foi” is a verb - they look or sound alike but fill different roles in a sentence.

#3,904
“fio” frequency rank
#26
“foi” frequency rank
3930
confusion score

Side-by-Side Comparison

Feature fio foi
Definition linha terceira pessoa do singular do pretérito perfeito do indicativo do verbo ser

Letter map: fio vs foi

Shared letters muted; letters that set fio and foi apart highlighted. Shared run: 2.

3 ch
fio
3 ch
foi

Part-of-speech tell for fio / foi

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: fio is anoun and foiaverb. On the page they differ only by swapping two adjacent letters (io ↔ oi) - a transposition the eye reads straight past. Our composite confusion score for this pair is 3930, derived from the frequency rank of both members and their visual similarity.

fio is recorded at frequency rank #3,904, classified as anoun. foi is at rank #26, tagged as averb, pronounced /ˈfoj/.

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 3930, this pair ranks #71,139 of 75,631 scored Portuguese confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of fio vs foi

Shared letters: fio. Private to "fio": -. Private to "foi": -.

"fio" · 3 letters · shape CVV  ·  "foi" · 3 letters · shape CVV

Frequently Asked Questions

Can "fio" and "foi" be used interchangeably?
No - they are not even the same part of speech. "fio" is a noun and "foi" a verb, so a sentence built for one is usually ungrammatical with the other.
Frequency check: "fio" vs "foi" - which ranks higher?
"foi" is the more common of the two: it sits at frequency rank #26 in our Portuguese list, against #3,904 for "fio". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

After this comparison

You've compared "fio" and "foi". Here's where to go from here.

  • Full dictionary entry for "fio" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "foi" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #71,139 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
  • "fio" and "foi" also get mixed up with nearby pairs, the highest-scored neighbour is "filão vs fio". Nearby pair

Confusion rank #71,139 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.

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

Source: FrequencyWords open word-frequency list