prolongvsprotonTell them apart

Quick tell: prolong is a verb, proton is a noun, so they fill different roles in a sentence.

Which to use

“prolong” is a verb and “proton” is a noun - they look or sound alike but fill different roles in a sentence.

#22,183
“prolong” frequency rank
#16,779
“proton” frequency rank
38962
confusion score

Side-by-Side Comparison

Feature prolong proton
Definition To extend in space or length. A positively charged subatomic particle forming part of the nucleus of an atom and determining the atomic number of an element, composed of two up quarks and a down quark.

Where the eye mixes prolong and proton

Muted = shared; highlighted = the visual trap. They share 5 letters in sequence. prolong runs 7 letters (CCVCVCC) against proton's 6 (CCVCVC) - the length gap alone is often enough to separate them once you know to check it.

7 ch
prolong
6 ch
proton

Visual trap between prolong and proton

These two trip readers on the page rather than in the ear: prolong is /pɹəʊˈlɒŋ/ while proton is /ˈpɹəʊ.tɒn/. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 letter(s) in length, and the parts of speech differ too (verb vs noun), which is usually the fastest check. Our composite confusion score for this pair is 38962, derived from the frequency rank of both members and their visual similarity.

prolong is recorded at frequency rank #22,183, classified as averb, pronounced /pɹəʊˈlɒŋ/. proton is at rank #16,779, tagged as anoun, pronounced /ˈpɹəʊ.tɒn/.

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 38962, this pair ranks #281,095 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of prolong vs proton

Shared letters: nopr. Private to "prolong": gl. Private to "proton": t.

"prolong" · 7 letters · shape CCVCVCC  ·  "proton" · 6 letters · shape CCVCVC

Known mistypes of this pair

  • prolong ← porlong · pprolong · prloong · prollong · prolnog · prologn · prolongg · prolonng
  • proton ← porton · pproton · prootn · protno · protonn · protton · prroton · prtoon

Frequently Asked Questions

Is swapping "prolong" for "proton" ever safe?
No - they are not even the same part of speech. "prolong" is a verb and "proton" a noun, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "prolong" or "proton"?
"proton" is the more common of the two: it sits at frequency rank #16,779 in our English list, against #22,183 for "prolong". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

What to do next

Eye-level mix-up between "prolong" and "proton" is sorted above. Next: full entries or other pairs that share a letter shape.

  • Full dictionary entry for "prolong" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "proton" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #281,095 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "prolong" and "proton" also get mixed up with nearby pairs, the highest-scored neighbour is "prolong vs prowling". 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 #281,095 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