sivssirWhat's the difference?

Quick tell: si is a conjunction, sir is a noun, so they fill different roles in a sentence.

Which to use

“si” is a conjunction and “sir” is a noun - they look or sound alike but fill different roles in a sentence.

#46
“si” frequency rank
#5,610
“sir” frequency rank
5656
confusion score

Side-by-Side Comparison

Feature si sir
Definition Dans le cas où, à condition que, supposé que. Note d’usage : Conjonction qui introduit une condition (suivie d’une conséquence) ou une supposition qui peut être supprimée en utilisant un conditionnel. Titre pour un chevalier, placé devant son prénom avec ou sans son nom de famille, mais non pas devant seulement son nom de famille.

Where the eye mixes si and sir

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

2 ch
si
3 ch
sir

Spelling & Dictionary Insight

These two trip readers on the page rather than in the ear: si is \si\ while sir is \ˈsɝ\. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 extra letter(s) - “si” sits inside “sir”, and the parts of speech differ too (conjunction vs noun), which is usually the fastest check. Our composite confusion score for this pair is 5656, derived from the frequency rank of both members and their visual similarity.

si is recorded at frequency rank #46, classified as aconj, pronounced \si\. sir is at rank #5,610, tagged as anoun, pronounced \ˈsɝ\.

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 5656, this pair ranks #428,412 of 440,172 scored French confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of si vs sir

Shared letters: is. Private to "si": -. Private to "sir": r.

"si" · 2 letters · shape CV  ·  "sir" · 3 letters · shape CVC

Frequently Asked Questions

Can "si" and "sir" be used interchangeably?
No - they are not even the same part of speech. "si" is a conjunction and "sir" a noun, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "si" or "sir"?
"si" is the more common of the two: it sits at frequency rank #46 in our French list, against #5,610 for "sir". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

What to do next

You've compared "si" and "sir". Here's where to go from here.

  • Full dictionary entry for "si" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "sir" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #428,412 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
  • "si" and "sir" also get mixed up with nearby pairs, the highest-scored neighbour is "sir vs suu". Nearby pair

PlainSpell is a reference corpus, not spelling advice. Verify unusual forms in context.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list