Abbreviations

Q. Could we have some prescriptions for sentence-initial “i.e.,” “e.g.,” “ibid.,” and the like in notes and parentheses? Capitalizing the first letter is widely felt to be awkward (see June Casagrande, “A Word, Please: A Guide to Using Latin Abbreviations, E.g. and I.e.,” December 12, 2015, in the Los Angeles Times), and at least one legal style guide prescribes lowercase “ibid.” at the beginning of a footnote (OSCOLA: Oxford University Standard for the Citation of Legal Authorities, 4th ed., Faculty of Law, 2012). Other style pundits have recommended periphrasis.

Q. In dialogue, when a character says “Nam” referring to Vietnam, is an apostrophe necessary? The official name is one word, yet “Viet Nam” is more historical. That would suggest the apostrophe is not needed?

Q. When an abbreviation is first mentioned in a footnote, should the abbreviation be spelled out in both the footnote and at the first mention of it in the body of the text, or is spelling it out in the footnote alone sufficient?

Q. I am seeing everywhere now that people are putting acronyms in parentheses instead of words, as in “Food and Drug Administration (FDA)” versus “FDA (Food and Drug Administration).” Can you explain to me why this is becoming more common? Parentheses have always been intended for additional information or words of further explanation, which is the opposite of an acronym. It just seems so backwards to me, and if you’re searching for what the acronym stands for, it’s hard to find because the acronym is in the parentheses and used from then on. Please help me understand the logic people are following with this style.

Q. What is the stance of CMOS on single-letter abbreviations for days of the week? In US higher education, the single-letter abbreviations (M, T, W, R, F, S, U) are ubiquitous, though I find no mention of these abbreviations being codified (ISO uses numbers). In prose, I often find myself using these abbreviations in lists of upcoming deadlines.

Q. When should you capitalize AM and PM?

Q. How do I abbreviate the word “number”?

Q. In CMOS 10.3, I am confused by the meaning of the following sentence, describing “less familiar abbreviations”: “Such an abbreviation should not be offered only once, never to be used again, except as an alternative form that may be better known to some readers.” Would you please clarify? Thank you!

Q. I have two questions about the use of AD (anno Domini). First, is it acceptable to leave the abbreviation after the year when it refers to a decade, as in “the 30s AD” (referring to the fourth decade)? Or should that be “the AD 30s”? Second, since AD literally means “in the year of the Lord,” should we avoid saying “in AD 60,” etc., just as we avoid saying “in ibid.”?

Q. Is it AKA, aka, or a.k.a.? What about in dialogue?