Question: Big fight about apostrophes at my writing group Saturday. Does a word ending in S, get an apostrophe S for possessive? Half say "absolutely" the other half scoff at the idea. Which is right? Marcy.
Answer: Actually both are right, depending on where they live. In US English, words ending in S get an apostrophe S, UNLESS they are plural possessives, according to the Chicago Manual of Style and some other US style books. In UK English, they get no s following the apostrophe, according to Strunk and White and other UK style manuals. Weird, huh?
For the record, in the US: Apostrophes are used in contractions, that is a shortened version of two words, but never in abbreviations. Can’t instead of can not, it’s for "it is" (the possessive form of “it” never takes an apostrophe), and didn’t instead of did not. But CDs, las an abbreviation, wouldn’t take an apostrophe. Apostrophes (usually apostrophe followed by an s) are used, for possessive clauses. Mandy’s house. Tammy’s CDs. Do you see what I mean? Possessive forms of proper names take an apostrophe s even if they already end in s, such as Silas’s car. But plural nouns and pronouns get the apostrophe without the s in the plural form. I visited Mandy’s parents’ house. Plural form of proper names get an “es” rather than a plain s, and no apostrophe. Both the following are correct. “The Williams’ car,” for possessive if the car belongs to the whole family, and “The Williamses came to dinner,” for plural.