s vs sei, What's the Difference?

Which to use

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

#511
“s” frequency rank: #118
“sei” frequency rank: 629
confusion score

Side-by-Side Comparison

Feature	s	sei
Definition	símbolo de segundo	expressa que aquilo ouvido que foi dito ou afirmado por alguém não é tomado como sendo a verdade

Letter map: s vs sei

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

1 ch

3 ch

sei

Role in the sentence - s and sei

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: s is asymbol and seianintj. On the page they differ by 2 extra letter(s) - “s” sits inside “sei”. Our composite confusion score for this pair is 629, derived from the frequency rank of both members and their visual similarity.

s is recorded at frequency rank #511, classified as asymbol. 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 629, this pair ranks #75,041 of 75,631 scored Portuguese confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of s vs sei

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

"s" · 1 letters · shape C · "sei" · 3 letters · shape CVV

Frequently Asked Questions

Can "s" and "sei" be used interchangeably?

No - they are not even the same part of speech. "s" is a symbol and "sei" an intj, so a sentence built for one is usually ungrammatical with the other.

Frequency check: "s" vs "sei" - which ranks higher?

"sei" is the more common of the two: it sits at frequency rank #118 in our Portuguese list, against #511 for "s". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

What to do next

Pair "s" vs "sei" is on the table, pick a follow-up below.

Full dictionary entry for "s" 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 #75,041 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
"s" and "sei" also get mixed up with nearby pairs, the highest-scored neighbour is "s vs Sau". Nearby pair

Confusion rank #75,041 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.