STI vs Sui, What's the Difference?

Which to use

“STI” is a noun and “Sui” is a name - they look or sound alike but fill different roles in a sentence.

#26,266
“STI” frequency rank: #28,040
“Sui” frequency rank: 54306
confusion score

Side-by-Side Comparison

Feature	STI	Sui
Definition	Initialism of sexually transmitted infection (also S.T.I.).	The Sui dynasty of China which ruled from 581 to 618.

Letter map: STI vs Sui

Shared letters muted; letters that set STI and Sui apart highlighted. Shared run: 2.

3 ch

STI

3 ch

Sui

Grammar separator: STI vs Sui

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: STI is anoun and Suianame. On the page they differ by a single letter - t in “STI” becomes u in “Sui”. Our composite confusion score for this pair is 54306, derived from the frequency rank of both members and their visual similarity.

STI is recorded at frequency rank #26,266, classified as anoun. Sui is at rank #28,040, tagged as aname, pronounced /sweɪ/.

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 54306, this pair ranks #142,102 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of STI vs Sui

Shared letters: is. Private to "STI": t. Private to "Sui": u.

"STI" · 3 letters · shape CCV · "Sui" · 3 letters · shape CVV

Frequently Asked Questions

Is swapping "STI" for "Sui" ever safe?

No - they are not even the same part of speech. "STI" is a noun and "Sui" a name, so a sentence built for one is usually ungrammatical with the other.

Which is more common, "STI" or "Sui"?

"STI" is the more common of the two: it sits at frequency rank #26,266 in our English list, against #28,040 for "Sui". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

What to do next

You've compared "STI" and "Sui". Here's where to go from here.

Full dictionary entry for "STI" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "Sui" - compare definitions side by side with the headword page. Word entry
This pair ranks #142,102 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
"STI" and "Sui" also get mixed up with nearby pairs, the highest-scored neighbour is "Sui vs sura". Nearby pair

Confusion rank #142,102 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.