iovsionWhat's the difference?

Which to use

“io” and “ion” are a confusable French pair: similar on the page, but distinct in meaning, check the gloss before you choose.

#23,588
“io” frequency rank
#14,064
“ion” frequency rank
37652
confusion score

Side-by-Side Comparison

Feature io ion
Definition Septième lettre de l’alphabet cyrillique, ё. Atome ou molécule ayant perdu ou gagné des électrons sur sa couche externe.

Where the eye mixes io and ion

Muted = shared; highlighted = the visual trap. They share 2 letters in sequence.

2 ch
io
3 ch
ion

Why the eye confuses io with ion

A purely visual mix-up. io (\jo\) and ion (\jɔ̃\) are said differently, so reading them aloud is the quickest way to catch the wrong one. On the page they stay close: they differ by 1 extra letter(s) - “io” sits inside “ion”. Our composite confusion score for this pair is 37652, derived from the frequency rank of both members and their visual similarity.

io is recorded at frequency rank #23,588, classified as anoun, pronounced \jo\. ion is at rank #14,064, tagged as anoun, pronounced \jɔ̃\.

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 37652, this pair ranks #260,940 of 440,172 scored French confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of io vs ion

Shared letters: io. Private to "io": -. Private to "ion": n.

"io" · 2 letters · shape VV  ·  "ion" · 3 letters · shape VVC

Frequently Asked Questions

Can "io" and "ion" be used interchangeably?
No. They are said differently (\jo\ versus \jɔ̃\) and carry different meanings; reading the sentence aloud is usually enough to catch the wrong one.
In ordinary French text, does "io" or "ion" show up more?
"ion" is the more common of the two: it sits at frequency rank #14,064 in our French list, against #23,588 for "io". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

What to do next

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

  • Full dictionary entry for "io" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "ion" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #260,940 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
  • "io" and "ion" also get mixed up with nearby pairs, the highest-scored neighbour is "io vs isi". Nearby pair

Confusion rank #260,940 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