ICOvsiffTell them apart

Quick tell: ICO is a noun, iff is a conjunction, so they fill different roles in a sentence.

Which to use

“ICO” is a noun and “iff” is a conjunction - they look or sound alike but fill different roles in a sentence.

#23,564
“ICO” frequency rank
#45,443
“iff” frequency rank
69007
confusion score

Side-by-Side Comparison

Feature ICO iff
Definition Initialism of initial coin offering. Abbreviation of if and only if.

Letter map: ICO vs iff

Shared letters muted; letters that set ICO and iff apart highlighted. Shared run: 1. ICO (VCV) and iff (VCC) run the same length but a different consonant-vowel pattern - the shape difference is usually the fastest tell.

3 ch
ICO
3 ch
iff

Part-of-speech tell for ICO / iff

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: ICO is anoun and iffaconjunction. On the page they share most of their letters but differ in 2 positions. Our composite confusion score for this pair is 69007, derived from the frequency rank of both members and their visual similarity.

ICO is recorded at frequency rank #23,564, classified as anoun. iff is at rank #45,443, tagged as aconj, pronounced /ɪf ən(d)ˈəʊn.li ɪf/.

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 69007, this pair ranks #56,411 of 530,003 scored English confusable pairs - among the most confusable pairs.

Orthographic DNA of ICO vs iff

Shared letters: i. Private to "ICO": co. Private to "iff": f.

"ICO" · 3 letters · shape VCV  ·  "iff" · 3 letters · shape VCC

Frequently Asked Questions

Do "ICO" and "iff" mean the same thing in a sentence?
No - they are not even the same part of speech. "ICO" is a noun and "iff" a conjunction, so a sentence built for one is usually ungrammatical with the other.
Frequency check: "ICO" vs "iff" - which ranks higher?
"ICO" is the more common of the two: it sits at frequency rank #23,564 in our English list, against #45,443 for "iff". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

What to do next

Done with this confusable. These links stay specific to "ICO" and "iff".

  • Full dictionary entry for "ICO" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "iff" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #56,411 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "ICO" and "iff" also get mixed up with nearby pairs, the highest-scored neighbour is "iff vs ith". Nearby pair

Confusion rank #56,411 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