Which to use
“fossa” and “FSA” are a confusable English pair: similar on the page, but distinct in meaning, check the gloss before you choose.
- #48,755
- “fossa” frequency rank
- #24,161
- “FSA” frequency rank
- 72916
- confusion score
Side-by-Side Comparison
| Feature | fossa | FSA |
|---|---|---|
| Definition | A pit, groove, cavity, or depression. | Initialism of flexible spending account or flexible spending arrangement. |
Letter map: fossa vs FSA
Shared letters muted; letters that set fossa and FSA apart highlighted. Shared run: 3. fossa runs 5 letters (CVCCV) against FSA's 3 (CCV) - the length gap alone is often enough to separate them once you know to check it.
Corpus notes: fossa and FSA
fossa and FSA are indexed as a confusable English pair. We have no recorded pronunciation or part of speech for both members, so the spelling overlap is what we can show you: they differ by 2 letter(s) in length. Our composite confusion score for this pair is 72916, derived from the frequency rank of both members and their visual similarity.
fossa is recorded at frequency rank #48,755, classified as anoun, pronounced /ˈfɒsə/. FSA is at rank #24,161, 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 72916, this pair ranks #41,390 of 530,003 scored English confusable pairs - among the most confusable pairs.
Orthographic DNA of fossa vs FSA
Shared letters: afs. Private to "fossa": o. Private to "FSA": -.
"fossa" · 5 letters · shape CVCCV · "FSA" · 3 letters · shape CCV
Known mistypes of this pair
- fossa ← ffossa · fosa · fosas · fsosa · ofssa
Frequently Asked Questions
Is swapping "fossa" for "FSA" ever safe?
Frequency check: "fossa" vs "FSA" - which ranks higher?
After this comparison
Pair "fossa" vs "FSA" is on the table, pick a follow-up below.
- Full dictionary entry for "fossa" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "FSA" - compare definitions side by side with the headword page. Word entry
- This pair ranks #41,390 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "fossa" and "FSA" also get mixed up with nearby pairs, the highest-scored neighbour is "fess vs fossa". 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 #41,390 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.