Round, square, or curly?

The punctuation marks that travel in pairs

Peter A. Goodwin, of Rockport, Mass., writes: “Can you comment on parentheses vs. brackets vs. braces?”

Gladly, Peter. In nontechnical American typography, parentheses are the usual thing. They tell the reader that what they enclose is an aside (a digression) or at any rate something that doesn’t affect the main point of the sentence.

• What’s in parentheses can be either a phrase (as here) or a sentence or more.

• Here’s an example of parens (this is what those of us who are on close terms with parentheses call them) around a complete sentence.

• And here’s how it goes when you want the sentence to end with what’s in parens (again, that’s what those of us who are on close terms with the things call them).

• But if the parenthetical sentence is parenthetical to the whole paragraph, that’s different. End the previous sentence with a period, then insert the open paren, initial cap the first word of the parenthetical sentence, and put an end period for the sentence inside the parens. (It’s really not as complicated as this may make it seem.)

Brackets come in when either:

• You put something parenthetical inside something that’s already parenthetical. (This doesn’t come up often [though some sources seem to think it does].)

• Or when you add to a quotation something that doesn’t occur in what you’re quoting: “Four score and seven [eighty-seven] years ago, our [ancestors] brought forth, on this continent,…” The bracketed addition may be explaining something in the quote “[eighty-seven]” or it may be replacing something, such as “[ancestors]” instead of the original “fathers,” because this is the 21st century and I’m woke, or woke-ish.

Braces {these guys} might in theory be used to make parenthetical something in brackets that’s inside parens — but don’t do this. It’s too weird. Braces do, though, frequently come up in software coding. And if you want to sound as if you’re well versed in coding, call parens “round brackets,” standard brackets “square brackets,” and braces “curly brackets.”

Email me with your language questions, peeves, problems, etc., at barbaraswordshop@gmail.com, and I’ll respond as soon as I can. Correspondence may be edited. If you subscribe to The Boston Globe, look for my column, “May I Have a Word,” in the Ideas section every other Sunday.