sãovsseiWhat's the difference?

Quick tell: são is a adjective, sei is an intj, so they fill different roles in a sentence.

Which to use

“são” is an adjective and “sei” is an intj - they look or sound alike but fill different roles in a sentence.

#34
“são” frequency rank
#118
“sei” frequency rank
152
confusion score

Side-by-Side Comparison

Feature são sei
Definition saudável expressa que aquilo ouvido que foi dito ou afirmado por alguém não é tomado como sendo a verdade

Letter map: são vs sei

Shared letters muted; letters that set são and sei apart highlighted. Shared run: 1.

3 ch
são
3 ch
sei

Role in the sentence - são and sei

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: são is anadjective and seianintj. On the page they share most of their letters but differ in 2 positions. Our composite confusion score for this pair is 152, derived from the frequency rank of both members and their visual similarity.

são is recorded at frequency rank #34, classified as anadj, pronounced /ˈsɐ̃w̃/. sei is at rank #118, tagged as anintj.

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 152, this pair ranks #75,500 of 75,631 scored Portuguese confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of são vs sei

Shared letters: s. Private to "são": . Private to "sei": ei.

"são" · 3 letters · shape CVV  ·  "sei" · 3 letters · shape CVV

Frequently Asked Questions

Is swapping "são" for "sei" ever safe?
No - they are not even the same part of speech. "são" is an adjective and "sei" an intj, so a sentence built for one is usually ungrammatical with the other.
In ordinary Portuguese text, does "são" or "sei" show up more?
"são" is the more common of the two: it sits at frequency rank #34 in our Portuguese list, against #118 for "sei". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

Done with this confusable. These links stay specific to "são" and "sei".

  • Full dictionary entry for "são" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "sei" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #75,500 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
  • "são" and "sei" also get mixed up with nearby pairs, the highest-scored neighbour is "são vs soap". Nearby pair

Confusion rank #75,500 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