caisvsciWhich spelling fits?

Quick tell: cais is a noun, ci is a pronoun, so they fill different roles in a sentence.

Which to use

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

#10,845
“cais” frequency rank
#19,655
“ci” frequency rank
30500
confusion score

Side-by-Side Comparison

Feature cais ci
Definition lugar à beira-mar, na margem do rio, nas estações de caminho-de-ferro ou do metropolitano apropriado para o embarque e desembarque de pessoas ou mercadorias tu, pronome pessoal sujeito da segunda pessoa do singular:

Where the eye mixes cais and ci

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

4 ch
cais
2 ch
ci

Why the eye confuses cais with ci

These two trip readers on the page rather than in the ear: cais is /ˈkajʃ/ while ci is /tsi/. Spoken aloud the problem disappears. In writing it persists, because they differ by 2 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 30500, derived from the frequency rank of both members and their visual similarity.

cais is recorded at frequency rank #10,845, classified as anoun, pronounced /ˈkajʃ/. ci is at rank #19,655, tagged as apron, pronounced /tsi/.

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 30500, this pair ranks #37,833 of 75,631 scored Portuguese confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of cais vs ci

Shared letters: ci. Private to "cais": as. Private to "ci": -.

"cais" · 4 letters · shape CVVC  ·  "ci" · 2 letters · shape CV

Known mistypes of this pair

  • caisacis · caiss · casi · ccais · cias

Frequently Asked Questions

Do "cais" and "ci" mean the same thing in a sentence?
No - they are not even the same part of speech. "cais" is a noun and "ci" a pronoun, so a sentence built for one is usually ungrammatical with the other.
In ordinary Portuguese text, does "cais" or "ci" show up more?
"cais" is the more common of the two: it sits at frequency rank #10,845 in our Portuguese list, against #19,655 for "ci". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

What to do next

Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.

  • Full dictionary entry for "cais" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "ci" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #37,833 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
  • "cais" and "ci" also get mixed up with nearby pairs, the highest-scored neighbour is "ci vs ciao". Nearby pair
  • Recorded mistypes exist for at least one side of this pair, useful when a spell-checker or OCR lands on the wrong form. See mistypes

Confusion rank #37,833 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