io vs iu, What's the Difference?

Which to use

“io” is an adverb and “iu” is an abbrev - they look or sound alike but fill different roles in a sentence.

#18,900
“io” frequency rank: #42,065
“iu” frequency rank: 60965
confusion score

Side-by-Side Comparison

Feature	io	iu
Definition	sempre	código de língua ISO 639-3 para a macrolíngua esquimó/inuktitut

Where the eye mixes io and iu

Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.

2 ch

Why the eye confuses io with iu

These two trip readers on the page rather than in the ear: io is /ˈi.o/, /ˈi.ɔ/ while iu is /ˈi.u/, /ˈi.ʊ/. Spoken aloud the problem disappears. In writing it persists, because they differ by a single letter - o in “io” becomes u in “iu”, and the parts of speech differ too (adverb vs abbrev), which is usually the fastest check. Our composite confusion score for this pair is 60965, derived from the frequency rank of both members and their visual similarity.

io is recorded at frequency rank #18,900, classified as anadv, pronounced /ˈi.o/, /ˈi.ɔ/. iu is at rank #42,065, tagged as anabbrev, pronounced /ˈi.u/, /ˈi.ʊ/.

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 60965, this pair ranks #7,385 of 75,631 scored Portuguese confusable pairs - among the most confusable pairs.

Orthographic DNA of io vs iu

Shared letters: i. Private to "io": o. Private to "iu": u.

"io" · 2 letters · shape VV · "iu" · 2 letters · shape VV

Frequently Asked Questions

Can "io" and "iu" be used interchangeably?

No - they are not even the same part of speech. "io" is an adverb and "iu" an abbrev, so a sentence built for one is usually ungrammatical with the other.

Which is more common, "io" or "iu"?

"io" is the more common of the two: it sits at frequency rank #18,900 in our Portuguese list, against #42,065 for "iu". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.

Full dictionary entry for "io" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "iu" - compare definitions side by side with the headword page. Word entry
This pair ranks #7,385 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
"io" and "iu" also get mixed up with nearby pairs, the highest-scored neighbour is "ino vs iu". Nearby pair

Confusion rank #7,385 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.