casovscoWhat's the difference?

Quick tell: caso is a conjunction, co is a pronoun, so they fill different roles in a sentence.

Which to use

“caso” is a conjunction and “co” is a pronoun - they look or sound alike but fill different roles in a sentence.

#181
“caso” frequency rank
#2,005
“co” frequency rank
2186
confusion score

Side-by-Side Comparison

Feature caso co
Definition na hipótese de; se que

Letter map: caso vs co

Shared letters muted; letters that set caso and co apart highlighted. Shared run: 2.

4 ch
caso
2 ch
co

Part-of-speech tell for caso / co

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: caso is aconjunction and coapronoun. On the page they differ by 2 letter(s) in length. Our composite confusion score for this pair is 2186, derived from the frequency rank of both members and their visual similarity.

caso is recorded at frequency rank #181, classified as aconj, pronounced /ˈka.zu/. co is at rank #2,005, 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 2186, this pair ranks #73,290 of 75,631 scored Portuguese confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of caso vs co

Shared letters: co. Private to "caso": as. Private to "co": -.

"caso" · 4 letters · shape CVCV  ·  "co" · 2 letters · shape CV

Known mistypes of this pair

  • casoacso · casso · ccaso · csao

Frequently Asked Questions

Can "caso" and "co" be used interchangeably?
No - they are not even the same part of speech. "caso" is a conjunction and "co" a pronoun, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "caso" or "co"?
"caso" is the more common of the two: it sits at frequency rank #181 in our Portuguese list, against #2,005 for "co". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

After this comparison

Done with this confusable. These links stay specific to "caso" and "co".

  • Full dictionary entry for "caso" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "co" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #73,290 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
  • "caso" and "co" also get mixed up with nearby pairs, the highest-scored neighbour is "ciao vs co". 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 #73,290 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