key vs Ku, What's the Difference?

Which to use

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

#788
“key” frequency rank: #14,350
“Ku” frequency rank: 15138
confusion score

Side-by-Side Comparison

Feature	key	Ku
Definition	An object designed to open and close a lock.	A surname from Korean.

Letter map: key vs Ku

Shared letters muted; letters that set key and Ku apart highlighted. Shared run: 1.

3 ch

key

2 ch

Part-of-speech tell for key / Ku

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: key is anoun and Kuaname. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 15138, derived from the frequency rank of both members and their visual similarity.

key is recorded at frequency rank #788, classified as anoun, pronounced /kiː/. Ku is at rank #14,350, tagged as aname.

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 15138, this pair ranks #465,833 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of key vs Ku

Shared letters: k. Private to "key": ey. Private to "Ku": u.

"key" · 3 letters · shape CVV · "Ku" · 2 letters · shape CV

Frequently Asked Questions

Is swapping "key" for "Ku" ever safe?

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

Frequency check: "key" vs "Ku" - which ranks higher?

"key" is the more common of the two: it sits at frequency rank #788 in our English list, against #14,350 for "Ku". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

Useful next steps

Done with this confusable. These links stay specific to "key" and "Ku".

Full dictionary entry for "key" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "Ku" - compare definitions side by side with the headword page. Word entry
This pair ranks #465,833 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
"key" and "Ku" also get mixed up with nearby pairs, the highest-scored neighbour is "Kop vs Ku". Nearby pair

Confusion rank #465,833 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.