iovsIonsWhich spelling fits?

Quick tell: io is a noun, Ions is a name, so they fill different roles in a sentence.

Which to use

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

#16,946
“io” frequency rank
#14,573
“Ions” frequency rank
31519
confusion score

Side-by-Side Comparison

Feature io Ions
Definition A type of moth, the io moth. A surname originating as a patronymic.

Letter map: io vs Ions

Shared letters muted; letters that set io and Ions apart highlighted. Shared run: 2.

2 ch
io
4 ch
Ions

Grammar separator: io vs Ions

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: io is anoun and Ionsaname. On the page they differ by 2 extra letter(s) - “io” sits inside “Ions”. Our composite confusion score for this pair is 31519, derived from the frequency rank of both members and their visual similarity.

io is recorded at frequency rank #16,946, classified as anoun, pronounced /ˈaɪəʊ/. Ions is at rank #14,573, 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 31519, this pair ranks #345,417 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of io vs Ions

Shared letters: io. Private to "io": -. Private to "Ions": ns.

"io" · 2 letters · shape VV  ·  "Ions" · 4 letters · shape VVCC

Known mistypes of this pair

  • Ionsinos · ionns · ionss · iosn · oins

Frequently Asked Questions

Do "io" and "Ions" mean the same thing in a sentence?
No - they are not even the same part of speech. "io" is a noun and "Ions" a name, so a sentence built for one is usually ungrammatical with the other.
In ordinary English text, does "io" or "Ions" show up more?
"Ions" is the more common of the two: it sits at frequency rank #14,573 in our English list, against #16,946 for "io". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

Pair "io" vs "Ions" is on the table, pick a follow-up below.

  • Full dictionary entry for "io" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "Ions" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #345,417 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "io" and "Ions" also get mixed up with nearby pairs, the highest-scored neighbour is "io vs ith". 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 #345,417 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.

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

Source: FrequencyWords open word-frequency list