Which to use
“fess” is a verb and “FIS” is a noun - they look or sound alike but fill different roles in a sentence.
- #43,640
- “fess” frequency rank
- #40,245
- “FIS” frequency rank
- 83885
- confusion score
Side-by-Side Comparison
| Feature | fess | FIS |
|---|---|---|
| Definition | To confess; to admit. | Initialism of flight information service. |
Letter map: fess vs FIS
Shared letters muted; letters that set fess and FIS apart highlighted. Shared run: 2. fess runs 4 letters (CVCC) against FIS's 3 (CVC) - the length gap alone is often enough to separate them once you know to check it.
Grammar separator: fess vs FIS
Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: fess is averb and FISanoun. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 83885, derived from the frequency rank of both members and their visual similarity.
fess is recorded at frequency rank #43,640, classified as averb, pronounced /fɛs/. FIS is at rank #40,245, tagged as anoun.
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 83885, this pair ranks #12,997 of 530,003 scored English confusable pairs - among the most confusable pairs.
Orthographic DNA of fess vs FIS
Shared letters: fs. Private to "fess": e. Private to "FIS": i.
"fess" · 4 letters · shape CVCC · "FIS" · 3 letters · shape CVC
Known mistypes of this pair
- fess ← efss · ffess · fses
Frequently Asked Questions
Can "fess" and "FIS" be used interchangeably?
In ordinary English text, does "fess" or "FIS" show up more?
Useful next steps
Pair "fess" vs "FIS" is on the table, pick a follow-up below.
- Full dictionary entry for "fess" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "FIS" - compare definitions side by side with the headword page. Word entry
- This pair ranks #12,997 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "fess" and "FIS" also get mixed up with nearby pairs, the highest-scored neighbour is "Fenn vs fess". 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 #12,997 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.