si vs sin, What's the Difference?

Which to use

“si” and “sin” are a confusable Portuguese pair: similar on the page, but distinct in meaning, check the gloss before you choose.

#482
“si” frequency rank: #8,687
“sin” frequency rank: 9169
confusion score

Side-by-Side Comparison

Feature	si	sin
Definition	refere-se à terceira pessoa, indica reflexividade e é usado após preposição (a, de, em, contra, sobre, por, etc., exceto com)	aquilo, aquele

Letter map: si vs sin

Shared letters muted; letters that set si and sin apart highlighted. Shared run: 2.

2 ch

3 ch

sin

Pair insight - si / sin

si and sin are indexed as a confusable Portuguese pair. We have no recorded pronunciation or part of speech for both members, so the spelling overlap is what we can show you: they differ by 1 extra letter(s) - “si” sits inside “sin”. Our composite confusion score for this pair is 9169, derived from the frequency rank of both members and their visual similarity.

si is recorded at frequency rank #482, classified as apron, pronounced /ˈsi/. sin is at rank #8,687, tagged as apron.

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 9169, this pair ranks #64,354 of 75,631 scored Portuguese confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of si vs sin

Shared letters: is. Private to "si": -. Private to "sin": n.

"si" · 2 letters · shape CV · "sin" · 3 letters · shape CVC

Frequently Asked Questions

Can "si" and "sin" be used interchangeably?

No. They differ by 1 extra letter(s) - “si” sits inside “sin”, but the dictionary glosses above give them different meanings, so swapping one for the other changes what the sentence says.

Which is more common, "si" or "sin"?

"si" is the more common of the two: it sits at frequency rank #482 in our Portuguese list, against #8,687 for "sin". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

Useful next steps

Pair "si" vs "sin" is on the table, pick a follow-up below.

Full dictionary entry for "si" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "sin" - compare definitions side by side with the headword page. Word entry
This pair ranks #64,354 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
"si" and "sin" also get mixed up with nearby pairs, the highest-scored neighbour is "Sau vs sin". Nearby pair

Confusion rank #64,354 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.