poisonvsprisonWhat's the difference?

Which to use

“poison” and “prison” are a confusable English pair: similar on the page, but distinct in meaning, check the gloss before you choose.

#6,282
“poison” frequency rank
#1,670
“prison” frequency rank
7952
confusion score

Side-by-Side Comparison

Feature poison prison
Definition A substance that is harmful or lethal to a living organism when ingested. A place or institution where people are held against their will, in the US especially for long-term confinement, as of those convicted of serious crimes or otherwise considered undesirable by the government.

Where the eye mixes poison and prison

Muted = shared; highlighted = the visual trap. They share 5 letters in sequence.

6 ch
poison
6 ch
prison

Look-alike desk: poison vs prison

A purely visual mix-up. poison (/ˈpɔɪ.zən/) and prison (/ˈpɹɪzn̩/) are said differently, so reading them aloud is the quickest way to catch the wrong one. On the page they stay close: they differ by a single letter - o in “poison” becomes r in “prison”. Our composite confusion score for this pair is 7952, derived from the frequency rank of both members and their visual similarity.

poison is recorded at frequency rank #6,282, classified as anoun, pronounced /ˈpɔɪ.zən/. prison is at rank #1,670, tagged as anoun, pronounced /ˈpɹɪzn̩/.

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 7952, this pair ranks #504,811 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of poison vs prison

Shared letters: inops. Private to "poison": -. Private to "prison": r.

"poison" · 6 letters · shape CVVCVC  ·  "prison" · 6 letters · shape CCVCVC

Known mistypes of this pair

  • poisonopison · pioson · poiosn · poisno · poisonn · posion · ppoison
  • prisonpirson · pprison · priosn · prisno · prisonn · prisson · prrison · prsion

Frequently Asked Questions

Do "poison" and "prison" mean the same thing in a sentence?
No. They are said differently (/ˈpɔɪ.zən/ versus /ˈpɹɪzn̩/) and carry different meanings; reading the sentence aloud is usually enough to catch the wrong one.
Which is more common, "poison" or "prison"?
"prison" is the more common of the two: it sits at frequency rank #1,670 in our English list, against #6,282 for "poison". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

What to do next

Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.

  • Full dictionary entry for "poison" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "prison" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #504,811 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "poison" and "prison" also get mixed up with nearby pairs, the highest-scored neighbour is "poison vs poon". 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 #504,811 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