Which to use
“sei” and “seis” are a confusable Spanish pair: similar on the page, but distinct in meaning, check the gloss before you choose.
- #48,072
- “sei” frequency rank
- #596
- “seis” frequency rank
- 48668
- confusion score
Side-by-Side Comparison
| Feature | sei | seis |
|---|---|---|
| Definition | Seis. | Cinco y uno. |
Where the eye mixes sei and seis
Muted = shared; highlighted = the visual trap. They share 3 letters in sequence. sei runs 3 letters (CVV) against seis's 4 (CVVC) - the length gap alone is often enough to separate them once you know to check it.
Why the eye confuses sei with seis
A purely visual mix-up. sei (/s̺ej/) and seis ([ˈsejs]) are said differently, so reading them aloud is the quickest way to catch the wrong one. On the page they stay close: they differ by 1 extra letter(s) - “sei” sits inside “seis”. Our composite confusion score for this pair is 48668, derived from the frequency rank of both members and their visual similarity.
sei is recorded at frequency rank #48,072, classified as anum, pronounced /s̺ej/. seis is at rank #596, tagged as anum, pronounced [ˈsejs].
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 48668, this pair ranks #113,168 of 323,831 scored Spanish confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of sei vs seis
Shared letters: eis. Private to "sei": -. Private to "seis": -.
"sei" · 3 letters · shape CVV · "seis" · 4 letters · shape CVVC
Known mistypes of this pair
- seis ← ceis · esis · seiss · sesi · sies · sseis
Frequently Asked Questions
Is swapping "sei" for "seis" ever safe?
Which is more common, "sei" or "seis"?
What to do next
Eye-level mix-up between "sei" and "seis" is sorted above. Next: full entries or other pairs that share a letter shape.
- Full dictionary entry for "sei" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "seis" - compare definitions side by side with the headword page. Word entry
- This pair ranks #113,168 of 323,831 scored Spanish confusable pairs in this corpus vintage. Corpus statistics
- "sei" and "seis" also get mixed up with nearby pairs, the highest-scored neighbour is "sei vs stem". 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 #113,168 of 323,831 scored Spanish pairs, corpus vintage 2026-09-03, not spelling advice.