ui vs uno, What's the Difference?

Which to use

“ui” is a noun and “uno” is a num - they look or sound alike but fill different roles in a sentence.

#23,979
“ui” frequency rank: #77
“uno” frequency rank: 24056
confusion score

Side-by-Side Comparison

Feature	ui	uno
Definition	Cebolla.	La cantidad de una cosa solitaria (a saber, sin otros).

Where the eye mixes ui and uno

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

2 ch

3 ch

uno

Look-alike desk: ui vs uno

These two trip readers on the page rather than in the ear: ui is [œy] while uno is [ˈuno]. 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 num), which is usually the fastest check. Our composite confusion score for this pair is 24056, derived from the frequency rank of both members and their visual similarity.

ui is recorded at frequency rank #23,979, classified as anoun, pronounced [œy]. uno is at rank #77, tagged as anum, pronounced [ˈuno].

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 24056, this pair ranks #242,909 of 323,831 scored Spanish confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of ui vs uno

Shared letters: u. Private to "ui": i. Private to "uno": no.

"ui" · 2 letters · shape VV · "uno" · 3 letters · shape VCV

Frequently Asked Questions

Is swapping "ui" for "uno" ever safe?

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

Frequency check: "ui" vs "uno" - which ranks higher?

"uno" is the more common of the two: it sits at frequency rank #77 in our Spanish list, against #23,979 for "ui". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

After this comparison

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

Full dictionary entry for "ui" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "uno" - compare definitions side by side with the headword page. Word entry
This pair ranks #242,909 of 323,831 scored Spanish confusable pairs in this corpus vintage. Corpus statistics
"ui" and "uno" also get mixed up with nearby pairs, the highest-scored neighbour is "ui vs UPN". Nearby pair

Confusion rank #242,909 of 323,831 scored Spanish pairs, corpus vintage 2026-09-03, not spelling advice.