Apostrophes
"Abolish the apostrophe and it will be necessary, before the hour is up, to reinvent it."
Wise words from Lynne Truss in the excellent Eats Shoots & Leaves, which we recommend to both punctuation lovers and loathers.
In the meantime, here's our guide on how to use your apostrophes appropriately.
Possession
Use " ’s " after singular nouns, plural nouns that don't end in "s", and indefinite pronouns:
The women’s toilet is over there.
For singular nouns that end in "s" or "z", let pronunciation be your guide:
James's thesis was longer than expected.
Socrates' life is recorded in Plato's dialogues.
Or consider rearranging the sentence:
The thesis that James submitted was longer than expected.
The life of Socrates is recorded in Plato's dialogues.
Use just ’ after plural nouns ending in "s":
In compound nouns (nouns consisting of more than one word) and where multiple nouns are linked, put the apostrophe at the end of the final part and match it to that noun:
Mitchell and Webb’s latest show.
The Sheriff of Nottingham’s appointment.
Interestingly, phrases such as collector’s item, cow’s milk, goat’s cheese and writer’s cramp are all treated as singular.
Periods of time
Use an apostrophe if you can replace the apostrophe with “of”:
This year’s agenda is yet to be decided. [The agenda of the year]
You must give three months’ notice. [Notice of three months]
But don't use an apostrophe where a time period is modifying an adjective:
She was eight months pregnant when she went into labour.
The baby is five weeks old today.
If in doubt, test it with a singular:
Place and street names
Some of these have an apostrophe and some don’t – there is no rhyme or reason to this, so you just have to look them up online, using the search engine of your choice.
Contractions
Use an apostrophe where the omitted letters would have been:
I'm sorry, but I don’t like that.
The dog's behaved well and we can tell it’s loyal.
Never use an apostrophe before contractions that are now accepted as words in their own right. It looks stilted and old fashioned:
I need to make a phone call.
See contractions for more examples.
Other important apostrophe rules
Don't use an apostrophe to make a plural:
The Labour movement changed greatly in the 1970s.
Never use an apostrophe to clarify something that would look odd if an "s" is added. You can always put it in quotation marks, but it's best to avoid it entirely if possible:
Dot the “i”s and cross the “t”s.