Which to use
“sei” is a num and “sum” is a noun - they look or sound alike but fill different roles in a sentence.
- #48,072
- “sei” frequency rank
- #27,789
- “sum” frequency rank
- 75861
- confusion score
Side-by-Side Comparison
| Feature | sei | sum |
|---|---|---|
| Definition | Seis. | Suma, adición. |
Where the eye mixes sei and sum
Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.
Visual trap between sei and sum
These two trip readers on the page rather than in the ear: sei is /s̺ej/ while sum is [sʌm]. Spoken aloud the problem disappears. In writing it persists, because they share most of their letters but differ in 2 positions, and the parts of speech differ too (num vs noun), which is usually the fastest check. Our composite confusion score for this pair is 75861, 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/. sum is at rank #27,789, tagged as anoun, pronounced [sʌm].
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 75861, this pair ranks #18,772 of 323,831 scored Spanish confusable pairs - among the most confusable pairs.
Orthographic DNA of sei vs sum
Shared letters: s. Private to "sei": ei. Private to "sum": mu.
"sei" · 3 letters · shape CVV · "sum" · 3 letters · shape CVC
Frequently Asked Questions
Is swapping "sei" for "sum" ever safe?
In ordinary Spanish text, does "sei" or "sum" show up more?
Useful next steps
Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.
- Full dictionary entry for "sei" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "sum" - compare definitions side by side with the headword page. Word entry
- This pair ranks #18,772 of 323,831 scored Spanish confusable pairs in this corpus vintage. Corpus statistics
- "sei" and "sum" also get mixed up with nearby pairs, the highest-scored neighbour is "sei vs stem". Nearby pair
Confusion rank #18,772 of 323,831 scored Spanish pairs, corpus vintage 2026-09-03, not spelling advice.