Q. Hi! Is it ever appropriate to follow an em dash with a period if it’s the terminus of the sentence? Thanks!
A. You could try it, but there are probably better options. When an em dash marks a midsentence interruption of one speaker by another, as in quoted dialogue, it’s best not to use any additional punctuation (see CMOS 6.87):
“I thought I might—”
“Might what?”
A period after the dash would suggest that the sentence had come to an end rather than having been interrupted. But even if the speaker breaks off and then resumes speaking without a paragraph break, a period wouldn’t be necessary:
“I thought I might— Oh, it’s no use.”
not
“I thought I might—. Oh, it’s no use.”
Either option could work (and note the space after the dash in the first one), but the period in the second example makes the break seem less sudden.
[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]
Q. How would you handle “early-to-mid” + “century”? “Early to mid-twentieth century”? “Early-to-mid twentieth century”? “Early-to-mid-twentieth century”?
A. When these century phrases are used as nouns, we’d retain only the hyphen after mid: “in the early twentieth century,” “in the mid-twentieth century,” and, by extension, “in the early to mid-twentieth century.” But when they’re used as modifiers before another noun, extra hyphenation would be needed: “early twentieth-century history,” “mid-twentieth-century history,” and “early-to-mid-twentieth-century history.”
Two things to note: (1) It wouldn’t be wrong to refer to “early-twentieth-century history” (with two hyphens), but we think the extra hyphen (after early) is unnecessary (see CMOS 7.87—and note that early is an adjective, not an adverb, and therefore not subject to the -ly exception described in CMOS 7.86). (2) The word mid, unlike early, isn’t an ordinary adjective; instead, it usually combines with any word that it modifies—either with a hyphen (“mid-twentieth”) or without (“midyear”).
See also the hyphenation guide at CMOS 7.89, section 1, under “number + noun”; section 3, under “century”; and section 4, under “mid.”
[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]
Q. Working on an architecture book that uses a lot of duplex addresses—i.e., 1522-1524 Main Street. Thought it should be an en, but someone pointed out the numbers are not inclusive, as 1523 Main Street is not part of the address. Is that correct? Should it just be a hyphen? Thanks!
A. Whoever pointed out that the numbers are not inclusive has a very good point. A hyphen is the better choice than an en dash in that context.
[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]
Q. Would it be correct to use an en dash instead of a hyphen in a compound like “singer-songwriter”? What about a slash?
A. En dashes may be used in compounds referring to two different people:
Epstein–Barr virus (a virus named for two people)
Ali–Frazier fight (a boxing match between two people)
a singer–songwriter duo (referring to two people)
but
Albers-Schönberg disease (a disease named for one person)
Though Chicago doesn’t require an en dash in those first three examples, some style guides do (notably in the sciences and in British English).
But when a compound refers to only one person or thing, as in the compound nouns singer-songwriter and city-state, most styles (including Chicago) would recommend using a hyphen.
As for a slash, that’s usually reserved for alternatives, where the slash means “or” rather than “and” (as in and/or but not singer/songwriter).
[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]
Q. Hi! Would “results sharing” be hyphenated in this example? “Each webcast includes in-session polling and results sharing.” Thanks!
A. According to our hyphenation guide (at CMOS 7.89, sec. 2), a compound noun that consists of a noun plus a gerund should be left open unless listed as either hyphenated or closed in Merriam-Webster. The term “results sharing” isn’t in M-W in any form, so leave it open.
[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]
Q. Hello! I understand that hyphens work like “treatment-naive patients” but “patients are treatment naive.” However, what would you recommend if the modifier is used alone—e.g., in a graph key? Hyphen or open? Should the key be “Treatment-naive” and “Previously treated,” or “Treatment naive” and “Previously treated”? Thank you!
A. Good question! Either approach would work, but we would lean slightly toward retaining the hyphen. The words “Treatment naive” as a standalone label lack the immediate context a sentence provides, making them prone to a momentary misreading without a hyphen (as they might be before a noun).
But we’d leave “Previously treated” alone as you’ve done; that term, thanks to that ly ending, wouldn’t be hyphenated in any context.
[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]
Q. Hi. I’m working on a label for an image in a printed brochure. The entire label is “bison shoulder blade hoe.” How would you punctuate that—with an en dash (“bison–shoulder blade hoe”)? Or hyphens (“bison-shoulder-blade hoe” or “bison shoulder-blade hoe”)? I was thinking that technically an en dash would be correct according to CMOS 6.80, but that seems too formal and, as CMOS states, unlikely to be noticed by most. There is no room to reword it. Thank you!
Q. Regarding open compounds, would an en dash be correct in “Mr. Potato Head–like head” and “rubbing alcohol–soaked cotton”? Thank you!
A. See CMOS 7.85: “With the exception of proper nouns (such as United States) and compounds formed by an adverb ending in ly plus an adjective (see 7.86), it is never incorrect to hyphenate adjectival compounds before a noun.” The goal of adding such hyphens is to clarify the meaning of the text.
To start with the bison, that example refers to a hoe fashioned from a bison’s shoulder blade. The three relevant terms are bison, shoulder blade, and hoe, so the clearest version is the last: “bison shoulder-blade hoe.”
We agree that an en dash wouldn’t work all that well; in “bison–shoulder blade hoe,” readers would need to recognize “shoulder blade” as a distinct compound before “hoe.” You’d be better off leaving the words open (“bison shoulder blade hoe”), trusting readers to sort out the modifiers without the help of hyphens or dashes. Or you could use two hyphens (“bison-shoulder-blade hoe”), but that doesn’t single out “shoulder blade” either, so the uncluttered open version is better.
As for the second question, it would be hard to improve on “Mr. Potato Head–like head,” where the en dash provides a perfect illustration of the principles covered in CMOS 6.80. And though the en dash is technically correct also in “rubbing alcohol–soaked cotton,” we’d advise rephrasing: “cotton soaked in rubbing alcohol.” Readers then won’t have to mentally sort out the string of modifiers to identify “rubbing alcohol,” a compound that, like “shoulder blade” in the bison example, lacks Mr. Potato Head’s prominent initial caps. Nor would “rubbing-alcohol soaked cotton” work; participles like “soaked” always require a hyphen in that position (see the hyphenation guide at CMOS 7.89, sec. 2, under “noun + participle”).
[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]
Q. Which is correct: “minimum food-safety standards” or “minimum food safety standards”? Thank you.
A. According to the hyphenation table at CMOS 7.89, a phrase like “food safety”—in which one noun (“food”) modifies another (“safety”)—would be hyphenated as a modifier before another noun. In other words, you’d write “food-safety standards” (with a hyphen). Adding “minimum” doesn’t change that: “minimum food-safety standards.”
That’s Chicago style, strictly interpreted, and you could stop there.
But a look at Google Ngram Viewer suggests that the phrase “food safety standards” has rarely appeared with a hyphen in published prose, maybe because standards for food safety and safety standards for food are pretty much the same thing, so a hyphen isn’t needed for clarity. A hyphen in the larger phrase—“minimum food-safety standards”—is a little more helpful (preventing a momentary misreading in which safety standards apply to “minimum food,” whatever that might be), but not much.
You’ve landed on one of those gray areas that tend to (or tends to?) drive writers and editors up the wall. A hyphen may help some readers—and it’s rarely considered wrong to add one in this scenario (see CMOS 7.85)—but it doesn’t seem to be customary in this particular phrase. If you’re looking to justify leaving it out, cite common usage and CMOS 7.84: “Where no ambiguity could result . . . hyphenation is unnecessary.”
[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]
Q. In your hyphenation guide, adjectival phrases are addressed: “Hyphenated before a noun; usually open after a noun.” Would the adjectival phrase “one-on-one” apply? The dictionary lists it only with hyphens, but I’m dealing with a sentence where it seems the hyphens would be unnecessary: “Coaches are available to meet one-on-one.”
A. In your example, “one-on-one” functions as an adverb rather than as an adjective (it modifies the verb to meet). And in general, a phrase that’s listed in Merriam-Webster with hyphens retains its hyphens if used as an adverb. Compare “day by day.” That expression, which is listed in Merriam-Webster without hyphens, would be hyphenated only as an adjective before a noun. For example, you would “take things day by day” (adv.) but “make a day-by-day assessment” (adj.).
[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]
Q. What is the correct way to hyphenate school grade levels, “fifth-grade” or “fifth grade”? And “fifth-grader” or “fifth grader”? Thank you.
A. Nouns like fifth grade and fifth grader are both left open:
Not all of us made it past the eighth grade.
Some second graders are more advanced than others.
Adjective forms, however, are hyphenated:
Our fifth-grade lessons included more writing than reading.
See also CMOS 7.89, section 1, under “number, ordinal, + noun.”
[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]