facvsfatWhat's the difference?

Quick tell: fac is a noun, fat is an adjective, so they fill different roles in a sentence.

Which to use

“fac” is a noun and “fat” is an adjective - they look or sound alike but fill different roles in a sentence.

#35,714
“fac” frequency rank
#1,482
“fat” frequency rank
37196
confusion score

Side-by-Side Comparison

Feature fac fat
Definition A factotum letter, or a similar kind of ornamentally bordered letter formerly used at the start of a chapter or section of a book. Carrying more fat than usual on one's body; plump; not lean or thin.

Where the eye mixes fac and fat

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

3 ch
fac
3 ch
fat

Why the eye confuses fac with fat

These two trip readers on the page rather than in the ear: fac is /fæk/ while fat is /ˈfæt/. Spoken aloud the problem disappears. In writing it persists, because they differ by a single letter - c in “fac” becomes t in “fat”, and the parts of speech differ too (noun vs adjective), which is usually the fastest check. Our composite confusion score for this pair is 37196, derived from the frequency rank of both members and their visual similarity.

fac is recorded at frequency rank #35,714, classified as anoun, pronounced /fæk/. fat is at rank #1,482, tagged as anadj, pronounced /ˈfæt/.

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 37196, this pair ranks #296,579 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of fac vs fat

Shared letters: af. Private to "fac": c. Private to "fat": t.

"fac" · 3 letters · shape CVC  ·  "fat" · 3 letters · shape CVC

Frequently Asked Questions

Can "fac" and "fat" be used interchangeably?
No - they are not even the same part of speech. "fac" is a noun and "fat" an adjective, so a sentence built for one is usually ungrammatical with the other.
In ordinary English text, does "fac" or "fat" show up more?
"fat" is the more common of the two: it sits at frequency rank #1,482 in our English list, against #35,714 for "fac". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

Useful next steps

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

  • Full dictionary entry for "fac" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "fat" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #296,579 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "fac" and "fat" also get mixed up with nearby pairs, the highest-scored neighbour is "fac vs foh". Nearby pair

Confusion rank #296,579 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