facvsflapWhich spelling fits?

Which to use

“fac” and “flap” are a confusable English pair: similar on the page, but distinct in meaning, check the gloss before you choose.

#35,714
“fac” frequency rank
#15,170
“flap” frequency rank
50884
confusion score

Side-by-Side Comparison

Feature fac flap
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. Anything broad and flexible that hangs loose, or that is attached by one side or end and is easily moved.

Where the eye mixes fac and flap

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

3 ch
fac
4 ch
flap

Why the eye confuses fac with flap

A purely visual mix-up. fac (/fæk/) and flap (/flæp/) 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 letter(s) in length. Our composite confusion score for this pair is 50884, 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/. flap is at rank #15,170, tagged as anoun, pronounced /flæp/.

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 50884, this pair ranks #170,308 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of fac vs flap

Shared letters: af. Private to "fac": c. Private to "flap": lp.

"fac" · 3 letters · shape CVC  ·  "flap" · 4 letters · shape CCVC

Known mistypes of this pair

  • flapfalp · fflap · flapp · fllap · flpa · lfap

Frequently Asked Questions

Is swapping "fac" for "flap" ever safe?
No. They are said differently (/fæk/ versus /flæp/) and carry different meanings; reading the sentence aloud is usually enough to catch the wrong one.
Which is more common, "fac" or "flap"?
"flap" is the more common of the two: it sits at frequency rank #15,170 in our English list, against #35,714 for "fac". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

After this comparison

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 "flap" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #170,308 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "fac" and "flap" also get mixed up with nearby pairs, the highest-scored neighbour is "fac vs foh". 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 #170,308 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