ao vs asa, What's the Difference?

Which to use

“ao” is a contraction and “asa” is a noun - they look or sound alike but fill different roles in a sentence.

#27
“ao” frequency rank: #7,104
“asa” frequency rank: 7131
confusion score

Side-by-Side Comparison

Feature	ao	asa
Definition	contração da preposição a com o artigo definido o	membro de um animal que serve para o voo

Where the eye mixes ao and asa

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

2 ch

3 ch

asa

Why the eye confuses ao with asa

These two trip readers on the page rather than in the ear: ao is /aw/ while asa is /ˈa.zɐ/. 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 (contraction vs noun), which is usually the fastest check. Our composite confusion score for this pair is 7131, derived from the frequency rank of both members and their visual similarity.

ao is recorded at frequency rank #27, classified as acontraction, pronounced /aw/. asa is at rank #7,104, tagged as anoun, pronounced /ˈa.zɐ/.

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 7131, this pair ranks #67,084 of 75,631 scored Portuguese confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of ao vs asa

Shared letters: a. Private to "ao": o. Private to "asa": s.

"ao" · 2 letters · shape VV · "asa" · 3 letters · shape VCV

Frequently Asked Questions

Can "ao" and "asa" be used interchangeably?

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

Which is more common, "ao" or "asa"?

"ao" is the more common of the two: it sits at frequency rank #27 in our Portuguese list, against #7,104 for "asa". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

What to do next

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

Full dictionary entry for "ao" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "asa" - compare definitions side by side with the headword page. Word entry
This pair ranks #67,084 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
"ao" and "asa" also get mixed up with nearby pairs, the highest-scored neighbour is "acs vs asa". Nearby pair

Confusion rank #67,084 of 75,631 scored Portuguese pairs, corpus vintage 2026-09-03, not spelling advice.