Which to use
“source” is a noun and “sure” is an adjective - they look or sound alike but fill different roles in a sentence.
- #743
- “source” frequency rank
- #202
- “sure” frequency rank
- 945
- confusion score
Side-by-Side Comparison
| Feature | source | sure |
|---|---|---|
| Definition | The person, place, or thing from which something (information, goods, etc.) comes or is acquired. | Physically secure and certain, non-failing, reliable. |
Where the eye mixes source and sure
Muted = shared; highlighted = the visual trap. They share 4 letters in sequence.
Visual trap between source and sure
These two trip readers on the page rather than in the ear: source is /sɔːs/ while sure is /ʃɔː(ɹ)/. Spoken aloud the problem disappears. In writing it persists, because they differ by 2 letter(s) in length, and the parts of speech differ too (noun vs adjective), which is usually the fastest check. Our composite confusion score for this pair is 945, derived from the frequency rank of both members and their visual similarity.
source is recorded at frequency rank #743, classified as anoun, pronounced /sɔːs/. sure is at rank #202, tagged as anadj, pronounced /ʃɔː(ɹ)/.
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 945, this pair ranks #528,458 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.
Orthographic DNA of source vs sure
Shared letters: ersu. Private to "source": co. Private to "sure": -.
"source" · 6 letters · shape CVVCCV · "sure" · 4 letters · shape CVCV
Known mistypes of this pair
Frequently Asked Questions
Is swapping "source" for "sure" ever safe?
Which is more common, "source" or "sure"?
After this comparison
Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.
- Full dictionary entry for "source" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "sure" - compare definitions side by side with the headword page. Word entry
- This pair ranks #528,458 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "source" and "sure" also get mixed up with nearby pairs, the highest-scored neighbour is "sura vs sure". 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 #528,458 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.