baivsbakWhich spelling fits?

Quick tell: bai is a preposition, bak is a noun, so they fill different roles in a sentence.

Which to use

“bai” is a preposition and “bak” is a noun - they look or sound alike but fill different roles in a sentence.

#27,371
“bai” frequency rank
#38,589
“bak” frequency rank
65960
confusion score

Side-by-Side Comparison

Feature bai bak
Definition de acordo com; conforme retaguarda, parte traseira

Where the eye mixes bai and bak

Muted = shared; highlighted = the visual trap. They share 2 letters in sequence. bai (CVV) and bak (CVC) run the same length but a different consonant-vowel pattern - the shape difference is usually the fastest tell.

3 ch
bai
3 ch
bak

Visual trap between bai and bak

These two trip readers on the page rather than in the ear: bai is /ba.ˈi/ while bak is /ˈbaːk/. Spoken aloud the problem disappears. In writing it persists, because they differ by a single letter - i in “bai” becomes k in “bak”, and the parts of speech differ too (preposition vs noun), which is usually the fastest check. Our composite confusion score for this pair is 65960, derived from the frequency rank of both members and their visual similarity.

bai is recorded at frequency rank #27,371, classified as aprep, pronounced /ba.ˈi/. bak is at rank #38,589, tagged as anoun, pronounced /ˈbaːk/.

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 65960, this pair ranks #5,163 of 75,631 scored Portuguese confusable pairs - among the most confusable pairs.

Orthographic DNA of bai vs bak

Shared letters: ab. Private to "bai": i. Private to "bak": k.

"bai" · 3 letters · shape CVV  ·  "bak" · 3 letters · shape CVC

Frequently Asked Questions

Can "bai" and "bak" be used interchangeably?
No - they are not even the same part of speech. "bai" is a preposition and "bak" a noun, so a sentence built for one is usually ungrammatical with the other.
In ordinary Portuguese text, does "bai" or "bak" show up more?
"bai" is the more common of the two: it sits at frequency rank #27,371 in our Portuguese list, against #38,589 for "bak". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

After this comparison

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

  • Full dictionary entry for "bai" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "bak" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #5,163 of 75,631 scored Portuguese confusable pairs in this corpus vintage. Corpus statistics
  • "bai" and "bak" also get mixed up with nearby pairs, the highest-scored neighbour is "bak vs bué". Nearby pair

Confusion rank #5,163 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