crux vs Cui, What's the Difference?

Which to use

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

#27,109
“crux” frequency rank: #39,761
“Cui” frequency rank: 66870
confusion score

Side-by-Side Comparison

Feature	crux	Cui
Definition	The basic, central, or essential point or feature.	A surname from Mandarin.

Letter map: crux vs Cui

Shared letters muted; letters that set crux and Cui apart highlighted. Shared run: 2. crux runs 4 letters (CCVC) against Cui's 3 (CVV) - the length gap alone is often enough to separate them once you know to check it.

4 ch

crux

3 ch

Cui

Grammar separator: crux vs Cui

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: crux is anoun and Cuianame. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 66870, derived from the frequency rank of both members and their visual similarity.

crux is recorded at frequency rank #27,109, classified as anoun, pronounced /kɹʌks/. Cui is at rank #39,761, 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 66870, this pair ranks #66,046 of 530,003 scored English confusable pairs - among the most confusable pairs.

Orthographic DNA of crux vs Cui

Shared letters: cu. Private to "crux": rx. Private to "Cui": i.

"crux" · 4 letters · shape CCVC · "Cui" · 3 letters · shape CVV

Known mistypes of this pair

crux ← ccrux · crrux · cruxx · crxu · curx · rcux

Frequently Asked Questions

Can "crux" and "Cui" be used interchangeably?

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

In ordinary English text, does "crux" or "Cui" show up more?

"crux" is the more common of the two: it sits at frequency rank #27,109 in our English list, against #39,761 for "Cui". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

Pair "crux" vs "Cui" is on the table, pick a follow-up below.

Full dictionary entry for "crux" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "Cui" - compare definitions side by side with the headword page. Word entry
This pair ranks #66,046 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
"crux" and "Cui" also get mixed up with nearby pairs, the highest-scored neighbour is "CGT vs Cui". 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 #66,046 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.