stovssuWhat's the difference?

Quick tell: sto is a preposition, su is a verb, so they fill different roles in a sentence.

Which to use

“sto” is a preposition and “su” is a verb - they look or sound alike but fill different roles in a sentence.

#31,269
“sto” frequency rank
#1,609
“su” frequency rank
32878
confusion score

Side-by-Side Comparison

Feature sto su
Definition Contraction de la préposition et de l'article défini, « dans le ». Participe passé masculin singulier du verbe savoir.

Where the eye mixes sto and su

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

3 ch
sto
2 ch
su

Look-alike desk: sto vs su

These two trip readers on the page rather than in the ear: sto is \sɛ\ while su is \sy\. 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 (preposition vs verb), which is usually the fastest check. Our composite confusion score for this pair is 32878, derived from the frequency rank of both members and their visual similarity.

sto is recorded at frequency rank #31,269, classified as aprep, pronounced \sɛ\. su is at rank #1,609, tagged as averb, pronounced \sy\.

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 32878, this pair ranks #294,346 of 440,172 scored French confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of sto vs su

Shared letters: s. Private to "sto": ot. Private to "su": u.

"sto" · 3 letters · shape CCV  ·  "su" · 2 letters · shape CV

Frequently Asked Questions

Is swapping "sto" for "su" ever safe?
No - they are not even the same part of speech. "sto" is a preposition and "su" a verb, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "sto" or "su"?
"su" is the more common of the two: it sits at frequency rank #1,609 in our French list, against #31,269 for "sto". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

After this comparison

Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.

  • Full dictionary entry for "sto" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "su" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #294,346 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
  • "sto" and "su" also get mixed up with nearby pairs, the highest-scored neighbour is "sto vs suu". Nearby pair

Confusion rank #294,346 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