Q. I’m confused about this issue of whether to add a space after the abbreviation “w/” (with). A previous answer said that there should be a space because the abbreviation stands for a full word, which would have a space after it if written out. But CMOS 6.116 shows no spaces around a slash that stands for “per” or that is used in an abbreviation like “c/o” (in care of) or “n/a” (not applicable). So why is “w/” treated differently?

A. In an expression like “km/s” (kilometers per second) or “$450/week” (450 dollars per week), the slash is a stand-alone abbreviation for “per.” If you were to add a space in either of those expressions, you’d need two of them (one before and one after the slash). In an expression like “c/o” or “n/a,” the slash is a kind of shorthand that tells readers to interpret the letters as abbreviations; it belongs equally to both letters.

The abbreviation “w/” is very much like “c/o” and “n/a” but with only one rather than two abbreviated letters. (Each of those could be written instead with periods, but the slash nonetheless became the convention.) But whereas c pairs with o and n with a, that w is, as our original answer suggested, a single entity that doesn’t normally pair with anything, so it’s usually separated from what comes next by a space.

That’s the editorial logic anyway. The abbreviation “w/” is casual. Any rule regarding its use should be taken w/ a grain of NaCl (and with the understanding that no rule is w/out exceptions).

Q. Is the following sentence correct? “Do the speaker or the characters have any specific personality traits that are highlighted throughout the poem?” According to CMOS 5.143, “When a verb has two or more subjects connected by or or nor, the verb agrees with the last-named subject” (e.g., “Bob or his friends have your key”; “neither the twins nor Jon is prepared to leave”). Based on that, it seems like it would be correct. “Characters” is closest to the verb, so that part is correct. I’m wondering if the auxiliary verb should match the verb or the subject closest to it? “Do the speaker or the characters have . . .” “Does the speaker or the characters have . . .” I’m probably overthinking this, but I can’t find any definitive answers when it comes to questions with compound subjects—one singular and one plural—joined by “or.” Could you point me to a rule that might address this? Thank you for your help.

A. We haven’t been able to find anything definitive either. So let’s try to invent something—we can call it the inverted-proximity rule—by adding on to the current wording in CMOS 5.143 (the new part is underlined):

When a verb has two or more subjects connected by or or nor, the verb agrees with the last-named subject; however, in a question that begins with an auxiliary verb, the auxiliary usually agrees with the first-named subject.

Here’s what that would look like relative to your example, starting with each subject used alone (and shortening your original predicate to make the examples easier to digest):

Does the speaker have any faults?

Do the characters have any faults?

Does the speaker or the characters have any faults?

That last example, where the auxiliary “Does” agrees with the subject “speaker,” seems to work well enough. But so does “Do the speaker or the characters have . . .” The problem with any rule based on a subject’s proximity to the verb is that a singular and a plural subject joined by or will tend to read as plural regardless of the order of subjects.

The remedy for questions, when you don’t like the result, is to put the plural subject first: “Do the characters or the speaker have any faults?” That fix can work for statements also: “Either Bob or his friends have your key” seems to work slightly better than “Either Bob’s friends or Bob has your key.”

In sum, for a plural and a singular subject joined by or (or nor), apply the proximity rule as stated above; if the result seems awkward, try switching the order of subjects.

Q. When referring to two doctors in a letter, should they be addressed as “Dr. A and Dr. B”? Or “Drs. A and B”?

A. For extra formality, use Drs., which echoes the old-fashioned Messrs. (the plural of Mr.) and would be especially well suited to the salutation. But if your letter isn’t especially formal, or if you’re simply naming the two doctors (as in the body of the letter), use Dr. before both names.

Q. According to CMOS 6.86, “The en dash can be used in place of a hyphen in a compound adjective when one of its elements consists of an open compound.” And according to 5.96, “If a compound noun is an element of a phrasal adjective, the entire compound noun must be hyphenated to clarify the relationship among the words,” as in the example “time-clock-punching employees.” But “time clock” is an open compound, so this seems contradictory. Am I misunderstanding something?

A. Those two paragraphs do seem to contradict each other, but it’s important to note that CMOS would recommend reworking the phrase “time clock–punching employees,” if possible, to avoid the need for an en dash. The problem is that more than a few readers will assume that the en dash is simply a kind of hyphen (if they notice the difference at all), which could result in a misreading, at least initially, of “clock-punching employees” who are somehow modified by “time.”

A phrase like “Civil War–era veterans,” by contrast, is a little easier to parse, thanks to the initial caps, which can help readers to understand that “Civil War” is a single term joined to the word “era.” The lowercase term “time clock,” though it’s common enough, doesn’t stand out in the same way. That’s why “country music–influenced lyrics” (the analogous example in CMOS 6.86) is followed by an alternative: “lyrics influenced by country music.”

We could have offered a second alternative: “country-music-influenced lyrics” (with two hyphens). But the noun phrase “country music” doesn’t seem to need a hyphen even when it’s used attributively before another noun, as in “country music lyrics,” which rarely appears anywhere with a hyphen (even though “country-music lyrics,” with a hyphen, wouldn’t be technically wrong; see CMOS 7.91 for a fuller explanation).

The phrase “time-clock punching,” however, seems to benefit from the hyphen, even though “time clock” is normally unhyphenated as a noun. That’s why “time-clock-punching employees”—where the whole phrase is used attributively—is our preference in CMOS (not only in chapter 5 but also in our hyphenation guide, section 1, under “noun + gerund”).

If you don’t like all those hyphens, try “employees who punch a time clock”—or, yes, use an en dash: “time clock–punching employees.” Some (many?) readers may not notice your en dash, but IYKYK.

Extra credit: What about “time-clock–punching employees,” with a hyphen and an en dash? That’s not a terrible idea (it does signal the hierarchy of relationships in the phrase), but it’s not Chicago style.

Q. In a series that contains titles with internal commas, would you use commas or semicolons to separate each item? For instance, how would you punctuate “the films The Good, the Bad and the Ugly, With Six You Get Eggroll, and Die, Monster, Die!”?

A. We’ve gotten many variations on this question over the years. In general, if a series is clear to you with commas, and you think it will be clear to your readers—and especially if you are resistant to semicolons or think they wouldn’t be a good fit for your document—then keep the commas. Otherwise, use semicolons instead; that’s what they’re for (among other things, as this sentence demonstrates).

Whether you choose commas or semicolons as separators, make sure you don’t italicize them along with the titles (any punctuation within a title remains in italics; see CMOS 6.2). For the lack of a serial comma in the title of the first movie (which follows the usage in that movie’s title sequence), see 8.167.

Q. I’m looking for a source for guidelines on what to display on a website when only one source is referenced in an online article. Is it okay to still put 1? I have previously been told by college professors and professional colleagues to substitute an asterisk instead.

A. If there’s a note number 1, readers may expect to find a note number 2 later in the same document. For that reason, using an asterisk instead of a number can make sense when there’s just one note. But there isn’t any general rule that we know of that says you must do this.

Let’s say, for example, that an academic journal uses author-date style supplemented by numbered notes for substantive comments, and that most articles in that journal include more than one note. It would be reasonable in that case, as a matter of consistency across articles, to assign a number even in the case of only one footnote.

So if you have the option of using an asterisk, consider doing so, but it’s not a requirement. For the answer to a similar question about whether to number a single figure in a document, see this Q&A (which links to the seventeenth edition of CMOS but still applies).