An Apostrophe

The Apostrophe is a diacritic mark in punctuation‏‎.

It is used in 2 different ways in English‏‎:

1. to show possessive nouns
2. to show omitted letters

Possession

Generally we add an apostrophe s to the end of a noun to make it possessive:

the girl’s bike

Maggie’s farm

If there is a plural noun‎ which ends in an -s, then we add the apostrophe after it but without the -s. In this case there are many girls who each have bikes:

the girls’ bikes

Compare these:

the lady’s bag
the ladies’ bags

a day’s work
three days’ holiday

In all these cases above the apostrophe -s goes on the singular and an apostrophe alone goes on the plural.

However, if there is a proper noun‏‎ ending in -s then we use an apostrophe without the -s (even though they’re singular):

Socrates’ philosphy

Euripedes’ works

Jesus’ sermons

In cases where several nouns are together, we have a choice. If the nouns form a single unit we use an apostrophe on the last noun only; if the nouns are to be treated as individual then we have an apostrophe for each one.

Here the wedding belongs to both the nouns:

It’s William and Kate’s wedding.

But in this case, we are talking about two different sets of parents:

William’s and Kate’s parents will attend the wedding.

Note that the apostrophe is not used with certain possessive words which on the surface might require one:

It’s hers.
It’s his
It’s theirs.
It’s yours.
It’s ours.
It’s its.

However, we do use an apostrophe when we use one.

One’s teeth chatter in this cold weather.

For more on using apostrophes (either with or without -s) to form the possessive, see the main article Possessive Apostrophes‏‎.

Omission

We also use an apostrophe to show where letters‏‎ have been removed from words:

don’t do it
it’s my turn
we should’ve gone earlier
during the ‘90s we lived in France

Greengrocers’ Apostrophes

It is not uncommon for native speakers to make mistakes with apostrophes, often using them to denote plurals or omitting them entirely. These are known as Greengrocers’ Apostrophes (or ironically as Greengrocers Apostrophe’s)

* Orange’s For Sale!

* Childrens Clothes

* Marion work’s for McDonald’s.

* An asterisk at the beginning of a sentence marks it as ungrammatical.