I understand that if you're speaking a phrase in which you would write parentheses, you can say the word parenthetically. But when should you write the word parenthetically?

I came across this sentence, starting off a paragraph in a scientific article:

Parenthetically, we note that subjects in all experimental conditions were unbiased …

This struck me as odd. If they're speaking parenthetically, shouldn't it be in parentheses? On the one hand, from a descriptive point of view, the usage of the word was not ambiguous – I know exactly what the author is trying to connote by using it. But from a prescriptive point of view, would this be considered proper grammar?

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    In the paper, if that sentence were enclosed in parentheses, the entire paragraph would need to be there too. Just saying parenthetically is the least awkward option. And possibly it implies a bit of "they make us say this, you know."
    – Chel
    Commented Jan 26, 2012 at 16:55
  • 3
    Parenthetically here functions as a sentence adverb. See this answer for more information.
    – Robusto
    Commented Jan 26, 2012 at 18:36
  • You would write it here: "Parenthetically". (Sorry, couldn't resist!) Commented Jan 30, 2012 at 6:04
  • parenthetically - to introduce a sentence or remark which is explanatory
    – user59538
    Commented Dec 12, 2013 at 5:00

7 Answers 7


The use of parenthetically is not limited to the literal meaning of appearing between brackets. It can, as in your example, mean simply ‘as an aside’.

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    Ah, so they were writing metaphorically parenthetically. Commented Jan 27, 2012 at 20:08
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    @TomAnderson: Quite so. Commented Jan 27, 2012 at 20:13
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    I think you mean "exactally". Commented Jan 27, 2012 at 20:18
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    @TomAnderson, To be fair, that's the original meaning of parenthesis. The ( and ) are called brackets. They're so often used to signify parenthesis to the extent that now people even call them that.
    – Pacerier
    Commented May 26, 2015 at 9:26

Don't confuse the punctuation marks routinely used to convey an idea with the idea itself, even when the punctuation marks have a same or similar name as the idea. It's quite reasonable to say, "Charles QUESTIONED the speaker's statement" without using a question mark (because I do not actually quote the question). "When I asked my children where they wanted to go for vacation, they EXCLAIMED that they wanted to go to Disney World." Etc.


In addition to its prescriptive purpose, parenthetically may also be used in a more abstract sense, by definition:

Set off within or as if within parentheses; qualifying or explanatory

It's worth noting that there is a difference between a parenthesis and parentheses, the former being a rhetoric device and the latter being punctuation. (Parentheses usually - but not always - enclose a parenthetical remark.)

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    Isn't parentheses just the plural of parenthesis. Since they're usually used in pairs in punctuation, you use the plural word for punctuation (although you would say "you're missing a right parenthesis here"). Commented Jan 26, 2012 at 17:16
  • @Peter Indeed. Both the punctuation mark and the rhetorical device share the same singular and plural forms, which adds to the confusion. See Pathenthesis (rhetoric) for further details.
    – HaL
    Commented Jan 26, 2012 at 17:23
  • @HaL, Your explanation in the answer is bad. Readers would think that there's a difference in spelling between the two concepts, but no, the two concepts are spelled identically.
    – Pacerier
    Commented May 26, 2015 at 9:29
  • @Pacerier: Feel free to edit this answer if it can be improved.
    – HaL
    Commented Jun 10, 2015 at 7:23

It's a good word to use in speech, when you can't show actual parentheses. In the context you give, it's probably just a stylistic choice, if an ill-advised one. Parenthetically, I note that scientific papers are not always models of perfect grammar and word choice.

  • Your last sentence eloquently refutes your second sentence. :-)
    – Zano
    Commented Jan 28, 2012 at 14:33

The word "parenthesis" is a Greek word, as every sophisticated word is... so, parenthesis (παρένθεσις) is exactly this: ( ). This is a parenthesis. When we say parenthetically, we mean that we add an idea to our text which it may seem unnecessary but we judge that it would enforce our point we wish to make.


I am mainly copying the entry because of the example below. Synonyms might help too



incidentally, by the way, in passing, by way of explanation, by the bye

This brings us, parenthetically, to another question.

Collins Thesaurus of the English Language – Complete and Unabridged 2nd Edition. 2002 © HarperCollins Publishers 1995, 2002


It seems to me that the use of the word parenthetically is used as a tangential idea separate from, but related, to the subject of the discourse.

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