I found some posts on whether it is acceptable to nest parentheses (e.g. here) but there is no discussion yet about which parentheses should be used when nesting, and how. These are some alternative methods that one could adopt to spell the same sentence with nested parentheses. Which one do you think is right?

  1. The nested and the nesting are in the same style

Example: Nested parentheses are ugly (as we saw in example (1), (2) and (3))

  1. Like in maths: nesting in square brackets, nested in simple

Example: Nested parentheses are ugly [as we saw in example (1), (2) and (3)]

  1. Internal parentheses need to go, and is substituted by some other sign

Example: Nested parentheses are ugly (as we saw in example -1-, -2- and -3-)

  1. External parentheses need to go (nesting is illegal)

Example: Nested parentheses are ugly, as we saw in example (1), (2) and (3)

My feeling is that (4) is preferable when possible, then (3), then (1). Clearly (4) will not always be possible (syntax may demand parentheses), and also (3) could create problems (for instance, it may introduce a confusing inconsistency in how one refers to the numbered examples). I find (2) almost offensive for a text in natural language (rather than mathematical notation).

I often find myself forced to used nested parentheses, even if I hate them. Any advice on which form is more acceptable would be very welcome!

  • 1
    This is definitely going to be opinion-based, but it's always an interesting question. With regard to your examples, I would just note that (1), (2) and (3) might be felt to be a different kind of entity to the typical piece of parenthesised material, since they are often used in numbered lists (e.g. exam questions).
    – legatrix
    Commented Dec 6, 2020 at 18:40
  • ...Hence I might prefer e.g. Nested parentheses are ugly (as we saw in our first (and worst) example).
    – legatrix
    Commented Dec 6, 2020 at 18:42
  • @legatrix Clarity and ease of parsing always trumping tidiness, I'd use square brackets for the inner parenthetical in your example. I agree that brackets around numerals are different from parenthetical brackets, and that different forms of brackets are ugly (so I stick to curved brackets where inner parentheticals are (reasonably) well away from the boundaries of the outer one). Commented Dec 8, 2020 at 15:11
  • Thanks @EdwinAshworth, it's true that I didn't list that option, although perhaps it can be seen as a variation of (3). I agree that square brackets for nested are better than squared brackets for nesting. Commented Dec 15, 2020 at 16:13

1 Answer 1


As already noted, it is a matter of opinion. I often come across this problem in my own writing, and usually try to avoid nesting by appropriate punctuation, most often by commas, sometimes colons, so I go with option (4). However, when writing concisely, it sometimes becomes unavoidable. In this case I allow myself to nest, as in option (1). For instance, consider

Nested parentheses are ugly (see Fig. 1(a)).

In this case, going with option 3 might be confusing for a reader, because figures are enumerated with letters in round brackets. Option (2) could be considered, but it is not consistent with other inclusions in the same text where a figure has no subfigures, for example: [see Fig. 1(a)] vs (see Fig. 2). If solution (4) cannot be adopted for some reason, I choose (1), never (2) or (3).

Terms, for which abbreviation needs to be introduced inside of parentheses, I usually separate from the abbreviation using en dash, e.g.,

nested parentheses (also known as ugly parentheses – UP),

instead of:

nested parentheses (also known as ugly parentheses (UP)).

However, in this case it is much easier to avoid nested parentheses than in case of figures' references.

  • Thanks, this is extremely helpful. I agree that it will mostly be a matter of opinion, but it also looks like some options will often be perceived as more elegant than others. And I do share your intuitions. The problem seems to arise mostly for numbered examples and figures, since for these cases (4) is typically unavailable; in these circumstances, (1) is typically the best option, I feel. Commented Dec 8, 2020 at 14:42

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