Possession may be nine-tenths of the apostrophe, but that alone is enough to throw the faint-hearted into panic.

You already know that John’s name and Jane’s address are possessive and singular, so they use apostrophe and “s.” But what happens when your hero’s name is James? Or Sass? Or Euripides? They’re singular, so the rule tells you to add an apostrophe and an “s,” but Canadian Press recommends going by the way they sound, and for what it’s worth GrammarPuss agrees. If the “s” at the end of the name (or word) you’re trying to make possessive sounds like an “s,” go ahead and add apostrophe-s. If, however, the “s” is pronounced “z,” leave off the “s” after the apostrophe: James’ and Euripides’, but Sass’s – even though the “s’s” looks funny, remember that when we read, most of us pronounce the words in our heads, even though we may do it faster than when speaking.

When the noun is plural and ends in “s,” always add just the apostrophe. If the noun doesn’t end in “s”, add both. You may be thinking, “Well, duh!” but childrens’ or mens’ are common errors. Children and men are both plural, therefore the correct formation is children’s and men’s.

In matters where two (or more) names are linked together, it’s necessary to decide whether the object is jointly possessed.

Here are some examples:

  • John and Jane’s marriage. (Implication: John and Jane are married to each other, i.e. one marriage, jointly possessed.)
  • John’s and Jane’s marriages. (Implication: John and Jane each have at least one marriage, but not to one another.)
  • John and Jane’s marriages. (Implication: John and Jane have been married to each more than once.)
  • Bush’s and Clinton’s policies. (Implication: Bush and Clinton each had policies; they were not the same policies.)
  • Bush and Clinton’s policies. (Implication: Bush and Clinton had policies in common. You’re right. It’s ridiculous. Never mind.)

Phrases that give possession to objects are fine in casual writing – again, just make sure the meaning is clear. The construction is the same: “The car’s and truck’s colours” implies that their colours are different. “The car and truck’s colours” implies that the vehicles are multi-coloured, and that those colours are the same on both. If you want to get really picky, objects should use “of” instead of the apostrophe, as in “the colour of the car,” but by all means, use the possessive when personifying objects, such as “death’s door” or “day’s dawning.”

The objects of actions should also use “of,” as in “the assassination of Kennedy,” although these days “Kennedy’s assassination” will slip by most copy editors. The possessive case and the “of” construction are largely interchangeable, just make sure the meaning is clear. We all know Kennedy was assassinated by Oswald, but the meaning of “Oswald’s assassination” is ambiguous. Going strictly on the information provided, the latter phrase could refer to Ruby’s assassination of Oswald or Oswald’s assassination of Kennedy.

Always be aware of the meaning you wish to convey, whether the object of an action or the possessor of an object. Compare “Jim’s painting” and “the painting of Jim’s.” Did he paint it? Or does he own it?

In modern grammar, the use of both “of” and the possessive apostrophe-s is common and widely accepted – “John is a friend of Jim’s,” rather than the technically-correct “John is a friend of Jim.”

Apostrophes are often used to create plurals. Use an apostrophe when its omission (er, I mean the omission of it) would confuse the reader, such as “Jimmy gets all straight As.” Huh? So, okay, he gets straight A’s. But he can certainly learn his ABCs, rather than his ABC’s. No confusion, no apostrophe.

Use apostrophes to replace omitted letters, such as in contractions like “can’t” or “shouldn’t” – I know you know this, but I’m getting to the point – and words like “li’l” for “little”, but do see that the apostrophe goes where the letter or letters would be. It’s not “l’il”. Unless it’s your new rap handle, in which case go nuts. This goes for numbers too – Happy Days took place in the ’50s, not the 50′s.

(My writing this article brings up another oft-misused possessive construction – the gerund, the “ing” verb. Use the possessive with gerunds. Our trying to make writers of ourselves. Her reading this newsletter. His [never him!] catching my typos. Your rapidly losing interest …)