The apostrophe: a punctuation mark used primarily to denote possession. Under-Ease: airtight underwear with a replaceable filter to remove foul gases before they escape. What could these two items possibly have in common?

Surprisingly, both captured the spotlight at the 2001 Ig Nobel Prizes, sponsored by the humour magazine Annals of Improbable Research and presented annually at Harvard to people whose achievements "cannot or should not be reproduced." That year the Ig Nobel prize for literature went to British journalist John Richards, founder of the Apostrophe Protection Society, for his efforts to protect, promote and defend the proper use of the apostrophe.

Those of us who respect the English language, with its myriad rules and conventions, may wonder. Why is the unassuming apostrophe the object of such mockery? How can its champion be lumped together with the forces against flatulence?

Apostrophe defenders can’t help but notice that this little mark is in grave trouble. Grocers promise fresh tomato’s. Computer manuals list users preferences. Restaurants boast the best donair’s in town. It seems apostrophes are scarce when they’re needed, plentiful when they’re not.

Possessive forms

The apostrophe most commonly shows ownership or possession. There are three basic rules for making nouns possessive:

  1. With nouns that do not end in s, add ’s.
    • Andy’s ideas
    • the children’s room
    • NATO’s members
    • the user’s preferences
    • the tomato’s seeds
    • women’s clothing
  2. With nouns that end in s and are plural, add just an apostrophe.
    • visitors’ comments
    • the twins’ room
    • the MacNeils’ house
    • the mushrooms’ stems
    • the books’ jackets
    • employees’ rights
  3. With nouns that end in s and are singular, add ’s—unless it makes the word too hard to pronounce, in which case add just an apostrophe.
    • the boss’s rules
    • James’s hairdo
    • Kansas’s plains


    • Euripides’ plays
    • Ulysses’ comrades
    • for goodness’ sake

Some constructions are more puzzling than others. Take multiple ownership, for instance. Generally speaking, if individuals own something together, the possessive belongs with only the last noun.

  • Suzanne and Jason’s apartment
  • Sonny and Cher’s music

If individuals own things separately, the possessive goes with each noun.

  • Ian’s, Thelma’s and Louise’s birthdays
  • the boys’ and girls’ washrooms

You may also wonder about the curiously redundant double possessive: that idea of Arnold’s, a friend of my father’s. Rest assured, this construction is common and entirely acceptable. It usually indicates that the thing possessed is one of several: Arnold has several ideas; my father has several friends.

And beware the seven deadly possessive pronouns, none of which takes an apostrophe: his, hers, theirs, yours, ours, its and whose. The last two, which plague apostrophe aficionados everywhere, are responsible for such howlers as the cat licked it’s paw (should be its) and who’s books are these? (should be whose). It helps to remember that it’s and who’s are contractions, short forms for it is/it has and who is/who has.

Certain plurals

Ig Nobel laureate John Richards verges on apoplectic when warning against the apostrophe with plurals. "Apostrophes are NEVER ever used to denote plurals!" his website shrieks. "Common examples of such abuse (all seen in real life!) are: Banana’s for sale which of course should read Bananas for sale . . . ." (If only Richards brought the same rigour to the comma, unaccountably absent from the above sentences, and to the colon, which incorrectly separates are from its subject complement.)

Sadly, in sounding this alarm our apostrophe protector goes too far. One cannot quibble with his example, nor with such egregious plurals as donair’s and tomato’s. But nearly all style guides and authorities agree that certain plurals can, and sometimes should, be formed with ’s. The most widely accepted are plurals of symbols, numerals, letters (especially lower-case), abbreviations (especially with periods) and words mentioned as words:

  • &’s
  • 6’s and 7’s
  • figure 8’s
  • p’s and q’s
  • c.o.d.’s
  • nine which’s, four that’s

Possessive or descriptive?

The apostrophe often appears, correctly, in constructions that are only loosely possessive:

  • the book’s sales
  • the report’s conclusion
  • the group’s representative

Even though these possessives fall outside the category of strict ownership, they can all be translated into an of phrase: the sales of the book, the conclusion of the report, the representative of the group. Remembering this helps with tricky possessives like one week’s vacation (a vacation of one week) and two cents’ worth (the worth of two cents).

In other cases, the noun may be more descriptive than possessive and may not translate into an of phrase. Here is where apostrophes become devilishly difficult. Two main rules prevail:

  1. When a noun is descriptive rather than possessive and ends in s, do not add an apostrophe.
    • a savings bank
    • a United Nations summit
    • a Knicks game
    • a World Series record
    • the appropriations group
    • the estimates division

    In these examples, the nouns ending in s serve as describers rather than possessors. Also, of phrases do not really work with them. Instead, other words are understood: a bank for savings, a summit by/for the United Nations, a game involving the Knicks, etc.

  2. When a noun is more descriptive than possessive and does not end in s, but is plural, add ’s.
    • the people’s bank
    • a children’s fund
    • the women’s credit union

The apostrophe’s idiosyncrasies

When it comes to names of organizations, places and other proper nouns, apostrophe use is a mind-bending hodgepodge. You can belong to the Editors’ Association of Canada or the Canadian Nurses Association. You can live in St. John’s, Newfoundland, or St. Andrews, New Brunswick (where, by the way, you might celebrate St. Andrew’s Day each November 30). In Ottawa you can buy groceries at Loblaws or Hartman’s, and grab a java at Starbucks or Timothy’s. The only sure way through this mess of contradictions is to check official spellings.

Its idiosyncrasies aside, the apostrophe merits the support offered it by Richards and his Apostrophe Protection Society. And others clearly agree: the society’s website has attracted more than 1.5 million visitors at the time of writing. True, apostrophe rules may not be as airtight as those prize-winning undergarments, but these few principles should put your mind, at least, at ease.

Related quiz

Test yourself—Apostroph-ease

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