Which to use
“theirs” is a pronoun and “theses” is a noun - they look or sound alike but fill different roles in a sentence.
- #7,623
- “theirs” frequency rank
- #22,243
- “theses” frequency rank
- 29866
- confusion score
Side-by-Side Comparison
| Feature | theirs | theses |
|---|---|---|
| Definition | That or those belonging to them; the possessive case of they, used without a following noun. | plural of thesis |
Where the spellings diverge
Shared letters are muted; the letters that actually set theirs and theses apart are highlighted. They share 4 letters in sequence, which is exactly why the eye skips the difference.
Spelling & Dictionary Insight
These two trip readers on the page rather than in the ear: theirs is /ðɛəz/ while theses is /ˈθiːsiːz/. Spoken aloud the problem disappears. In writing it persists, because they share most of their letters but differ in 2 positions, and the parts of speech differ too (pronoun vs noun), which is usually the fastest check. Our composite confusion score for this pair is 29866, derived from the frequency rank of both members and their visual similarity.
theirs is recorded at frequency rank #7,623, classified as apron, pronounced /ðɛəz/. theses is at rank #22,243, tagged as anoun, pronounced /ˈθiːsiːz/.
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 29866, this pair ranks #359,386 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of theirs vs theses
Shared letters: ehst. Private to "theirs": ir. Private to "theses": -.
"theirs" · 6 letters · shape CCVVCC · "theses" · 6 letters · shape CCVCVC
Known mistypes of this pair
Frequency comparison
Frequently Asked Questions
Can "theirs" and "theses" be used interchangeably?
Which is more common, "theirs" or "theses"?
Remembering theirs vs theses
The fastest way to pick the right one every time.
- Check the role first: if you need a pronoun, it's “theirs”; for a noun, it's “theses”.
- See each word in full, definition, IPA, etymology and its other confusables. Full “theirs” entry
- Browse more pairs most likely to be confused. Most confusable