parenthesesvsparenthesisWhat's the difference?

Which to use

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

#24,539
“parentheses” frequency rank
#45,571
“parenthesis” frequency rank
70110
confusion score

Side-by-Side Comparison

Feature parentheses parenthesis
Definition plural of parenthesis A clause, phrase or word which is inserted (usually for explanation or amplification) into a passage which is already grammatically complete, and usually marked off with brackets, commas or dashes.

Where the eye mixes parentheses and parenthesis

Muted = shared; highlighted = the visual trap. They share 10 letters in sequence.

11 ch
parentheses
11 ch
parenthesis

Look-alike desk: parentheses vs parenthesis

A purely visual mix-up. parentheses (/pəˈɹɛnθəsiːz/) and parenthesis (/pəˈɹɛnθəsɪs/) 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 - e in “parentheses” becomes i in “parenthesis”. Our composite confusion score for this pair is 70110, derived from the frequency rank of both members and their visual similarity.

parentheses is recorded at frequency rank #24,539, classified as anoun, pronounced /pəˈɹɛnθəsiːz/. parenthesis is at rank #45,571, tagged as anoun, pronounced /pəˈɹɛnθəsɪs/.

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 70110, this pair ranks #51,887 of 530,003 scored English confusable pairs - among the most confusable pairs.

Orthographic DNA of parentheses vs parenthesis

Shared letters: aehnprst. Private to "parentheses": -. Private to "parenthesis": i.

"parentheses" · 11 letters · shape CVCVCCCVCVC  ·  "parenthesis" · 11 letters · shape CVCVCCCVCVC

Known mistypes of this pair

  • parenthesesaprentheses · paerntheses · parenhteses · parenntheses · parentehses · parentheess · parenthesess · parenthesse
  • parenthesisaprenthesis · paernthesis · parenhtesis · parennthesis · parentehsis · parentheiss · parenthesiss · parenthessi

Frequently Asked Questions

Is swapping "parentheses" for "parenthesis" ever safe?
No. They are said differently (/pəˈɹɛnθəsiːz/ versus /pəˈɹɛnθəsɪs/) and carry different meanings; reading the sentence aloud is usually enough to catch the wrong one.
Which is more common, "parentheses" or "parenthesis"?
"parentheses" is the more common of the two: it sits at frequency rank #24,539 in our English list, against #45,571 for "parenthesis". 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 "parentheses" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "parenthesis" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #51,887 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • 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 #51,887 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