Punctuating Style in CMOS 17: What’s New with Colons, Commas, Dashes, and Slashes
Note: This article originally appeared in Copyediting newsletter, which explains the low word-to-humor ratio, and is reproduced with permission.
The following updates introduce new rules or clarify old ones for added finesse and flexibility.
- When introducing a list or series, the words preceding the colon no longer need to be a grammatically complete sentence if the verb is understood: New: metadata, abstracts, and keywords.
- Reword the sentence when the serial comma causes ambiguity. When the serial comma might be misread as framing an appositive, one solution is to repeat the conjunction: Instead of she drove her wife, the teacher, and her mother, use she drove her wife and the teacher and her mother.
- Use a comma after “etc.,” “et al.,” and “and so forth” only if required by the surrounding text. Instead of setting these terms off with a pair of commas according to the previous recommendation, treat them as equivalent to the final element in a series: The editor donated a dozen outdated reference books (without removing dog-ears, pencil marks, sticky notes, etc. from the pages).
- Capitalize the first word of a direct question not enclosed in quotation marks when it follows a comma. Another departure from previous editions, this guideline makes this category of question analogous to a direct quotation: He wondered, Should I track changes?
- It’s not necessary to precede the adverbs “too” and “either” with a comma when used in the sense of “also” at the end of a sentence. They couldn’t make the deadline either. The printer was down too.
- In correspondence, a greeting containing a direct address requires two punctuations: a comma in the direct address and a colon or comma after the greeting.
Welcome, readers: . . . Hi, Laura, . . .
But in casual correspondence, the direct-address comma is often omitted.
Hi Erin, . . .
Visit CMOS Shop Talk for Chicago style–related news, advice, and quizzes.
- In printed publications, break the line after an em dash, not before. But when another punctuation mark immediately follows the dash, like in this example, keep the elements together:
“I’m saving my edits before I—” the student said as the computer froze.
- In printed publications, break the line after an en dash, not before. But if it pushes a single character to the next line, such as part of a number range or a score, keep the elements together.
- An en dash with a space before and after may be used instead of an em dash in running text. Primarily a British style, an en dash as em dash is preferred by many U.S. publishers and writers.
- In printed publications, break the line after a slash, not before. But if it pushes a single character to the next line (such as when it is part of a two-year span) or splits a fraction, keep the elements together. This new rule doesn’t apply to poetry line breaks (break before or after) or URLs (break before).
Multiple Punctuation Marks
- Except in formal prose, a question mark can be combined with an exclamation point to “express excitement or disbelief.” Are we another step closer to adopting the interrobang?!