Which to use
“sour” is an adjective and “sum” is a noun - they look or sound alike but fill different roles in a sentence.
- #8,610
- “sour” frequency rank
- #4,050
- “sum” frequency rank
- 12660
- confusion score
Side-by-Side Comparison
| Feature | sour | sum |
|---|---|---|
| Definition | Tasting of acidity. | A quantity obtained by addition or aggregation. |
Where the eye mixes sour and sum
Muted = shared; highlighted = the visual trap. They share 2 letters in sequence.
Visual trap between sour and sum
These two trip readers on the page rather than in the ear: sour is /ˈsaʊə/ while sum is /sʌm/. 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 (adjective vs noun), which is usually the fastest check. Our composite confusion score for this pair is 12660, derived from the frequency rank of both members and their visual similarity.
sour is recorded at frequency rank #8,610, classified as anadj, pronounced /ˈsaʊə/. sum is at rank #4,050, 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 12660, this pair ranks #480,267 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.
Orthographic DNA of sour vs sum
Shared letters: su. Private to "sour": or. Private to "sum": m.
"sour" · 4 letters · shape CVVC · "sum" · 3 letters · shape CVC
Known mistypes of this pair
- sour ← osur · soru · sourr · ssour · suor
Frequently Asked Questions
Do "sour" and "sum" mean the same thing in a sentence?
Which is more common, "sour" or "sum"?
Useful next steps
Eye-level mix-up between "sour" and "sum" is sorted above. Next: full entries or other pairs that share a letter shape.
- Full dictionary entry for "sour" 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 #480,267 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "sour" and "sum" also get mixed up with nearby pairs, the highest-scored neighbour is "sour vs sura". 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 #480,267 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.