sinusvssisWhat's the difference?

Quick tell: sinus is a noun, sis is an adjective, so they fill different roles in a sentence.

Which to use

“sinus” is a noun and “sis” is an adjective - they look or sound alike but fill different roles in a sentence.

#26,185
“sinus” frequency rank
#19,157
“sis” frequency rank
45342
confusion score

Side-by-Side Comparison

Feature sinus sis
Definition Formation anatomique creuse, liquidienne ou pneumatique. Qui est situé.

Where the eye mixes sinus and sis

Muted = shared; highlighted = the visual trap. They share 3 letters in sequence.

5 ch
sinus
3 ch
sis

Look-alike desk: sinus vs sis

These two trip readers on the page rather than in the ear: sinus is \si.nys\ while sis is \si\. Spoken aloud the problem disappears. In writing it persists, because they differ by 2 letter(s) in length, and the parts of speech differ too (noun vs adjective), which is usually the fastest check. Our composite confusion score for this pair is 45342, derived from the frequency rank of both members and their visual similarity.

sinus is recorded at frequency rank #26,185, classified as anoun, pronounced \si.nys\. sis is at rank #19,157, tagged as anadj, pronounced \si\.

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 45342, this pair ranks #203,428 of 440,172 scored French confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of sinus vs sis

Shared letters: is. Private to "sinus": nu. Private to "sis": -.

"sinus" · 5 letters · shape CVCVC  ·  "sis" · 3 letters · shape CVC

Known mistypes of this pair

  • sinusisnus · sinnus · sinsu · sinuss · siuns · snius · ssinus

Frequently Asked Questions

Do "sinus" and "sis" mean the same thing in a sentence?
No - they are not even the same part of speech. "sinus" is a noun and "sis" an adjective, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "sinus" or "sis"?
"sis" is the more common of the two: it sits at frequency rank #19,157 in our French list, against #26,185 for "sinus". 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 "sinus" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "sis" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #203,428 of 440,172 scored French confusable pairs in this corpus vintage. Corpus statistics
  • "sinus" and "sis" also get mixed up with nearby pairs, the highest-scored neighbour is "sinus vs sires". 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 #203,428 of 440,172 scored French pairs, corpus vintage 2026-09-03, not spelling advice.

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

Source: FrequencyWords open word-frequency list