Which to use
“per” is a preposition and “petri” is a noun - they look or sound alike but fill different roles in a sentence.
- #339
- “per” frequency rank
- #29,786
- “petri” frequency rank
- 30125
- confusion score
Side-by-Side Comparison
| Feature | per | petri |
|---|---|---|
| Definition | For each. | Ellipsis of petri dish. |
Where the eye mixes per and petri
Muted = shared; highlighted = the visual trap. They share 3 letters in sequence.
Visual trap between per and petri
These two trip readers on the page rather than in the ear: per is /pɜː/ while petri is /ˈpiːtɹi/. 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 (preposition vs noun), which is usually the fastest check. Our composite confusion score for this pair is 30125, derived from the frequency rank of both members and their visual similarity.
per is recorded at frequency rank #339, classified as aprep, pronounced /pɜː/. petri is at rank #29,786, tagged as anoun, pronounced /ˈpiːtɹi/.
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 30125, this pair ranks #357,146 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of per vs petri
Shared letters: epr. Private to "per": -. Private to "petri": it.
"per" · 3 letters · shape CVC · "petri" · 5 letters · shape CVCCV
Known mistypes of this pair
- petri ← eptri · perti · petir · petrri · pettri · ppetri · pteri
Frequently Asked Questions
Can "per" and "petri" be used interchangeably?
Which is more common, "per" or "petri"?
Useful next steps
Eye-level mix-up between "per" and "petri" is sorted above. Next: full entries or other pairs that share a letter shape.
- Full dictionary entry for "per" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "petri" - compare definitions side by side with the headword page. Word entry
- This pair ranks #357,146 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
- "per" and "petri" also get mixed up with nearby pairs, the highest-scored neighbour is "Petey vs petri". 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 #357,146 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.