Mind Those Apostrophes

When editors are asked to name their pet peeves, misuse of apostrophes ranks at or near the top of their list. The apostrophe, more than any other punctuation mark, is likely to be overused.

The Chicago of Manual of Style names only three primary uses for an apostrophe:

• to show possession

Most singular (regular) nouns show possession by adding an apostrophe + s: horse’s mouth; company’s policy; Jamie’s daughter. An apostrophe is a less cumbersome way to show possession than the prepositional phrase the mouth belonging to the horse.

The possessive of most plural nouns is formed by adding an apostrophe after the s: girls’ toys, books’ pages, clocks’ batteries. However, in the case of nouns that do not add an s to form their plural, e.g. man – men, woman – women, child – children – the possessive is formed the same way as singular nouns: apostrophe + s.

In the case of nouns that end in s, the 16th (latest) edition of CMOS comes down on the side of apostrophe + s, thus Des Moines’s mayor attended the conference; Descartes’s thesis was included in the syllabus are the proper renderings.

• to indicate missing letters

Use an apostrophe to indicate missing letters. Common contractions are the combination of a pronoun and verb such as we are – we’re; he/she is – he’s/she’s; they have – they’ve and be-verbs and most of the auxiliary verbs when followed by not: are not – aren’t; was not – wasn’t; have not – haven’t.

(It takes all my restraint, not to insert an apostrophe in this plaque hanging in my son and daughter-in-law’s home. In this case, family harmony trumps punctuation.)

• and, to form the plurals of lower case letters.

Here, Chicago opts for a visual rather than a grammatical choice. In phrases like, “Mind your p’s and q’s,” apostrophes are used simply for ease in reading. But note that “dos and don’ts” rates only the apostrophe for the contraction don’t.

Don’t use an apostrophe in these situations:

• to form the plural of a family name. We went along with the Smiths to the beach.
• in possessive pronouns: hers, his, theirs, its, yours, etc.
• when capital letters are used as words. Capital Bank’s IRAs are earning a higher interest rate than First Federal’s.
• numerals are used as nouns. The hits from the 1990s continue to attract listeners. (No apostrophe in 1990s.)
• abbreviations are plural. Fred and Edna cashed in their CDs to fund their retirement expenses.