Which to use
“rex” and “RSF” are a confusable French pair: similar on the page, but distinct in meaning, check the gloss before you choose.
- #12,467
- “rex” frequency rank
- #44,703
- “RSF” frequency rank
- 57170
- confusion score
Side-by-Side Comparison
| Feature | rex | RSF |
|---|---|---|
| Definition | Race de chat, à queue longue ou moyenne et à poil court et ondulé car il n’est constitué que du sous-poil. | Abréviation de réacteur à sels fondus. |
Where the eye mixes rex and RSF
Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.
Why the eye confuses rex with RSF
A purely visual mix-up. rex (\ʁɛks\) and RSF (\ɛ.ʁɛ.sɛf\) are said differently, so reading them aloud is the quickest way to catch the wrong one. On the page they stay close: they share most of their letters but differ in 2 positions. Our composite confusion score for this pair is 57170, derived from the frequency rank of both members and their visual similarity.
rex is recorded at frequency rank #12,467, classified as anoun, pronounced \ʁɛks\. RSF is at rank #44,703, tagged as anoun, pronounced \ɛ.ʁɛ.sɛf\.
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 57170, this pair ranks #116,651 of 440,172 scored French confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of rex vs RSF
Shared letters: r. Private to "rex": ex. Private to "RSF": fs.
"rex" · 3 letters · shape CVC · "RSF" · 3 letters · shape CCC
Frequently Asked Questions
Can "rex" and "RSF" be used interchangeably?
Frequency check: "rex" vs "RSF" - which ranks higher?
What to do next
Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.
- Full dictionary entry for "rex" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "RSF" - compare definitions side by side with the headword page. Word entry
- This pair ranks #116,651 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
- "rex" and "RSF" also get mixed up with nearby pairs, the highest-scored neighbour is "rog vs RSF". Nearby pair
Confusion rank #116,651 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.