os vs Ost, What's the Difference?

Which to use

“os” is an article and “Ost” is a noun - they look or sound alike but fill different roles in a sentence.

#19
“os” frequency rank: #27,958
“Ost” frequency rank: 27977
confusion score

Side-by-Side Comparison

Feature	os	Ost
Definition	usado para apontar um nome definido, único	leste

Where the eye mixes os and Ost

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

2 ch

3 ch

Ost

Visual trap between os and Ost

These two trip readers on the page rather than in the ear: os is /uʃ/, /us/ (menos frequente); enfático: /oʃ/, /os/ (menos frequente) while Ost is /ɔst/. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 extra letter(s) - “os” sits inside “Ost”, and the parts of speech differ too (article vs noun), which is usually the fastest check. Our composite confusion score for this pair is 27977, derived from the frequency rank of both members and their visual similarity.

os is recorded at frequency rank #19, classified as anarticle, pronounced /uʃ/, /us/ (menos frequente); enfático: /oʃ/, /os/ (menos frequente). Ost is at rank #27,958, tagged as anoun, pronounced /ɔst/.

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 27977, this pair ranks #40,916 of 75,631 scored Portuguese confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of os vs Ost

Shared letters: os. Private to "os": -. Private to "Ost": t.

"os" · 2 letters · shape VC · "Ost" · 3 letters · shape VCC

Frequently Asked Questions

Can "os" and "Ost" be used interchangeably?

No - they are not even the same part of speech. "os" is an article and "Ost" a noun, so a sentence built for one is usually ungrammatical with the other.

Frequency check: "os" vs "Ost" - which ranks higher?

"os" is the more common of the two: it sits at frequency rank #19 in our Portuguese list, against #27,958 for "Ost". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

After this comparison

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

Full dictionary entry for "os" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "Ost" - compare definitions side by side with the headword page. Word entry
This pair ranks #40,916 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
"os" and "Ost" also get mixed up with nearby pairs, the highest-scored neighbour is "oni vs Ost". Nearby pair

Confusion rank #40,916 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.