ubvsubiWhat's the difference?

Quick tell: ub is a noun, ubi is an adverb, so they fill different roles in a sentence.

Which to use

“ub” is a noun and “ubi” is an adverb - they look or sound alike but fill different roles in a sentence.

#41,579
“ub” frequency rank
#42,101
“ubi” frequency rank
83680
confusion score

Side-by-Side Comparison

Feature ub ubi
Definition Eau. Où, en quel endroit.

Where the eye mixes ub and ubi

Muted = shared; highlighted = the visual trap. They share 2 letters in sequence. ub runs 2 letters (VC) against ubi's 3 (VCV) - the length gap alone is often enough to separate them once you know to check it.

2 ch
ub
3 ch
ubi

Why the eye confuses ub with ubi

These two trip readers on the page rather than in the ear: ub is \u˧˥\ while ubi is \ˈu.biː\. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 extra letter(s) - “ub” sits inside “ubi”, and the parts of speech differ too (noun vs adverb), which is usually the fastest check. Our composite confusion score for this pair is 83680, derived from the frequency rank of both members and their visual similarity.

ub is recorded at frequency rank #41,579, classified as anoun, pronounced \u˧˥\. ubi is at rank #42,101, tagged as anadv, pronounced \ˈu.biː\.

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 83680, this pair ranks #14,381 of 440,172 scored French confusable pairs - among the most confusable pairs.

Orthographic DNA of ub vs ubi

Shared letters: bu. Private to "ub": -. Private to "ubi": i.

"ub" · 2 letters · shape VC  ·  "ubi" · 3 letters · shape VCV

Frequently Asked Questions

Is swapping "ub" for "ubi" ever safe?
No - they are not even the same part of speech. "ub" is a noun and "ubi" an adverb, so a sentence built for one is usually ungrammatical with the other.
Frequency check: "ub" vs "ubi" - which ranks higher?
"ub" is the more common of the two: it sits at frequency rank #41,579 in our French list, against #42,101 for "ubi". 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 "ub" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "ubi" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #14,381 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
  • "ub" and "ubi" also get mixed up with nearby pairs, the highest-scored neighbour is "ubi vs Ubu". Nearby pair

Confusion rank #14,381 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list