Which to use
“STA” is a name and “STI” is a noun - they look or sound alike but fill different roles in a sentence.
- #19,212
- “STA” frequency rank
- #26,266
- “STI” frequency rank
- 45478
- confusion score
Side-by-Side Comparison
| Feature | STA | STI |
|---|---|---|
| Definition | Initialism of State Transport Authority. | Initialism of sexually transmitted infection (also S.T.I.). |
Letter map: STA vs STI
Shared letters muted; letters that set STA and STI apart highlighted. Shared run: 2.
Role in the sentence - STA and STI
Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: STA is aname and STIanoun. On the page they differ by a single letter - a in “STA” becomes i in “STI”. Our composite confusion score for this pair is 45478, derived from the frequency rank of both members and their visual similarity.
STA is recorded at frequency rank #19,212, classified as aname. STI is at rank #26,266, tagged as anoun.
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 45478, this pair ranks #220,920 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of STA vs STI
Shared letters: st. Private to "STA": a. Private to "STI": i.
"STA" · 3 letters · shape CCV · "STI" · 3 letters · shape CCV
Frequently Asked Questions
Is swapping "STA" for "STI" ever safe?
Which is more common, "STA" or "STI"?
After this comparison
You've compared "STA" and "STI". Here's where to go from here.
- Full dictionary entry for "STA" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "STI" - compare definitions side by side with the headword page. Word entry
- This pair ranks #220,920 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "STA" and "STI" also get mixed up with nearby pairs, the highest-scored neighbour is "Sif vs STI". Nearby pair
Confusion rank #220,920 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.