sci vs si, What's the Difference?

Which to use

“sci” is a noun and “si” is a pronoun - they look or sound alike but fill different roles in a sentence.

#29,904
“sci” frequency rank: #482
“si” frequency rank: 30386
confusion score

Side-by-Side Comparison

Feature	sci	si
Definition	esqui, placa geralmente de madeira para deslizar na água ou na neve	refere-se à terceira pessoa, indica reflexividade e é usado após preposição (a, de, em, contra, sobre, por, etc., exceto com)

Where the eye mixes sci and si

Muted = shared; highlighted = the visual trap. They share 2 letters in sequence.

3 ch

sci

2 ch

Look-alike desk: sci vs si

These two trip readers on the page rather than in the ear: sci is /ˈʃi/ while si is /ˈsi/. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 letter(s) in length, and the parts of speech differ too (noun vs pronoun), which is usually the fastest check. Our composite confusion score for this pair is 30386, derived from the frequency rank of both members and their visual similarity.

sci is recorded at frequency rank #29,904, classified as anoun, pronounced /ˈʃi/. si is at rank #482, tagged as apron, pronounced /ˈsi/.

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 30386, this pair ranks #37,978 of 75,631 scored Portuguese confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of sci vs si

Shared letters: is. Private to "sci": c. Private to "si": -.

"sci" · 3 letters · shape CCV · "si" · 2 letters · shape CV

Frequently Asked Questions

Is swapping "sci" for "si" ever safe?

No - they are not even the same part of speech. "sci" is a noun and "si" a pronoun, so a sentence built for one is usually ungrammatical with the other.

Frequency check: "sci" vs "si" - which ranks higher?

"si" is the more common of the two: it sits at frequency rank #482 in our Portuguese list, against #29,904 for "sci". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

Useful next steps

Eye-level mix-up between "sci" and "si" is sorted above. Next: full entries or other pairs that share a letter shape.

Full dictionary entry for "sci" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "si" - compare definitions side by side with the headword page. Word entry
This pair ranks #37,978 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
"sci" and "si" also get mixed up with nearby pairs, the highest-scored neighbour is "Sau vs sci". Nearby pair

Confusion rank #37,978 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.