“A parentheses” or “a parenthesis”: which is correct?
a parenthesis
The short answer
Parenthesis is the correct singular form of the noun, referring to one of the curved marks (like this: ( or )). Parentheses is the correct plural form, referring to the pair.
Why people get it wrong
People often confuse the singular and plural forms of words, especially when the plural form doesn’t just add an s. Parentheses is one such word, where the singular is parenthesis, and the plural is parentheses. Since both forms sound similar, mixing them up is a common mistake.
What kind of mistake it is
Singular vs. plural usage error
Examples with a parenthesis
- There is a parenthesis in the middle of the sentence.
- Please use parentheses to enclose this phrase.
- A single parenthesis was left open.
- Remember to add a parenthesis at the end.
Quick check
There is in the middle of the sentence.
Parenthesis is the correct singular form of the noun, referring to one of the curved marks (like this: ( or )). Parentheses is the correct plural form, referring to the pair.
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