Q. Hi, I see that CMOS 8.36 discusses kinship names and when to capitalize versus when to lowercase. I’m wondering about a term like “sir” or “ma’am” used in direct address: “Yes, ma’am” or “Yes, Ma’am”? I think probably the former, but what do you recommend? Thank you.
A. You’re right to prefer lowercase. Terms like “sir” and “ma’am” are almost never used literally as titles these days. Instead they’re more often like common nouns or pronouns, as in “Hello, stranger,” or “Hey, you.” So unless you are transcribing a conversation with Sir Paul McCartney or Dame Judi Dench (two modern celebrities on whom titles have been conferred; see CMOS 8.32), write “Yes, sir” and “Yes, ma’am.” Compare “Greetings, Doctor.” In that case, “Doctor” is a proper noun standing in for a person’s name in the form “Dr. Surname.” But these distinctions can be fuzzy; when in doubt—or to convey a less formal tone—use lowercase.