key vs ku, What's the Difference?

Which to use

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

#18,292
“key” frequency rank: #29,714
“ku” frequency rank: 48006
confusion score

Side-by-Side Comparison

Feature	key	ku
Definition	Llave.	Ese, esa. Pronombre y adjetivo demostrativo usado para una entidad ausente.

Where the eye mixes key and ku

Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.

3 ch

key

2 ch

Visual trap between key and ku

These two trip readers on the page rather than in the ear: key is [kiː] while ku is [ˈku]. 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 (noun vs pronoun), which is usually the fastest check. Our composite confusion score for this pair is 48006, derived from the frequency rank of both members and their visual similarity.

key is recorded at frequency rank #18,292, classified as anoun, pronounced [kiː]. ku is at rank #29,714, tagged as apron, pronounced [ˈku].

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 48006, this pair ranks #116,854 of 323,831 scored Spanish confusable pairs - roughly mid-pack for confusability.

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 pronoun, 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 #18,292 in our Spanish list, against #29,714 for "ku". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.

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 #116,854 of 323,831 scored Spanish confusable pairs in this corpus vintage. Corpus statistics
"key" and "ku" also get mixed up with nearby pairs, the highest-scored neighbour is "kar vs ku". Nearby pair

Confusion rank #116,854 of 323,831 scored Spanish pairs, corpus vintage 2026-09-03, not spelling advice.