CassvscosWhich spelling fits?

Quick tell: Cass is a name, cos is a noun, so they fill different roles in a sentence.

Which to use

“Cass” is a name and “cos” is a noun - they look or sound alike but fill different roles in a sentence.

#14,714
“Cass” frequency rank
#6,553
“cos” frequency rank
21267
confusion score

Side-by-Side Comparison

Feature Cass cos
Definition A diminutive of the female given name Cassandra of medieval origin, later also used for Cassidy, and Catherine with its variant forms. Synonym of romaine lettuce, a long-leaved variety of lettuce.

Letter map: Cass vs cos

Shared letters muted; letters that set Cass and cos apart highlighted. Shared run: 2.

4 ch
Cass
3 ch
cos

Role in the sentence - Cass and cos

Our dataset has no pronunciation recorded for both members, so the reliable separator here is grammatical: Cass is aname and cosanoun. On the page they differ by 1 letter(s) in length. Our composite confusion score for this pair is 21267, derived from the frequency rank of both members and their visual similarity.

Cass is recorded at frequency rank #14,714, classified as aname. cos is at rank #6,553, tagged as anoun, pronounced /kɑs/.

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 21267, this pair ranks #425,108 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of Cass vs cos

Shared letters: cs. Private to "Cass": a. Private to "cos": o.

"Cass" · 4 letters · shape CVCC  ·  "cos" · 3 letters · shape CVC

Known mistypes of this pair

  • Cassacss · ccass · csas

Frequently Asked Questions

Do "Cass" and "cos" mean the same thing in a sentence?
No - they are not even the same part of speech. "Cass" is a name and "cos" a noun, so a sentence built for one is usually ungrammatical with the other.
Frequency check: "Cass" vs "cos" - which ranks higher?
"cos" is the more common of the two: it sits at frequency rank #6,553 in our English list, against #14,714 for "Cass". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

Done with this confusable. These links stay specific to "Cass" and "cos".

  • Full dictionary entry for "Cass" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "cos" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #425,108 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "Cass" and "cos" also get mixed up with nearby pairs, the highest-scored neighbour is "Cass vs CSX". 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 #425,108 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.

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

Source: FrequencyWords open word-frequency list