Which to use
“auto” is a noun and “aux” is a contraction - they look or sound alike but fill different roles in a sentence.
- #871
- “auto” frequency rank
- #32,511
- “aux” frequency rank
- 33382
- confusion score
Side-by-Side Comparison
| Feature | auto | aux |
|---|---|---|
| Definition | Vehículo de cuatro ruedas, cerrado, con asientos, propulsado por un motor de combustión o eléctrico, destinado al transporte de una a cinco personas. | Contracción de la preposición à y el artículo les; a las ; a los. |
Where the eye mixes auto and aux
Muted = shared; highlighted = the visual trap. They share 2 letters in sequence.
Visual trap between auto and aux
These two trip readers on the page rather than in the ear: auto is [ˈawt̪o] while aux is /o/. 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 (noun vs contraction), which is usually the fastest check. Our composite confusion score for this pair is 33382, derived from the frequency rank of both members and their visual similarity.
auto is recorded at frequency rank #871, classified as anoun, pronounced [ˈawt̪o]. aux is at rank #32,511, tagged as acontraction, pronounced /o/.
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 33382, this pair ranks #197,094 of 323,831 scored Spanish confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of auto vs aux
Shared letters: au. Private to "auto": ot. Private to "aux": x.
"auto" · 4 letters · shape VVCV · "aux" · 3 letters · shape VVC
Known mistypes of this pair
- auto ← atuo · auot · autto · uato
Frequently Asked Questions
Can "auto" and "aux" be used interchangeably?
Frequency check: "auto" vs "aux" - which ranks higher?
What to do next
Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.
- Full dictionary entry for "auto" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "aux" - compare definitions side by side with the headword page. Word entry
- This pair ranks #197,094 of 323,831 scored Spanish confusable pairs in this corpus vintage. Corpus statistics
- "auto" and "aux" also get mixed up with nearby pairs, the highest-scored neighbour is "atl vs aux". 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 #197,094 of 323,831 scored Spanish pairs, corpus vintage 2026-09-03, not spelling advice.