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' Apostrophe

Many students find it difficult to use the apostrophe. Using it wrongly can change the meaning and it is something which really irritates readers.

Video clips - lecturers' comments
Lecturer Name: Chris Hopkins
Lecturer Description: Teaches English in the Faculty of Society and Development

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Text transcript


Lecturer Name: Steve Harriman
Lecturer Description: Teaches Communications in the Faculty of Arts, Computing, Engineering and Science (ACES)

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The good news is that the rules about its use are easy and consistent.

The following describes 3 main uses for the apostrophe.

To show possession

Here, the apostrophe shows that something belongs to somebody or to something.

  • The apostrophe goes with the word which shows the owner.
  • If the owner is singular (one), add s and put the apostrophe before the s.
  • If the owner is plural (more than one) the apostrophe goes right at the end of the word (see below for rare exceptions).

If you get this wrong, the reader may be confused about what belongs to what.


The car's colour
This means the colour of the car.

The cars' colour
This means the colour of the cars.

The country's language
This means the language of the country.

*The countrys' language
This is incorrect. There is no such word as countrys. The plural (more than one) of country is countries. If you mean of more than one country it should be countries'.

Where a word means a collection of things, such as herd (of cows), you treat it as any singular word.


The herd's home
This means the home of the herd.

The herds' home
This means the home of several herds.


The plural (more than one) of some words does not end in s. Here you add an s and put the apostrophe in front of it. To show possession you must have an s.


The plural of criterion is criteria.
The assessment criteria's main purpose
This means the main purpose of the assessment criteria (more than one).

*The assessment criterions' main purpose
This is incorrect. There is no such word as criterions.

These are correct.
The children's house
The men's shoes

These are incorrect.
*The childrens' house
*The mens' shoes

Where a person's name ends in s it is equally acceptable to have s' or s's.


James' book
James's book

Pronouns do not use the apostrophe. A pronoun is used instead of a noun to avoid having to keep repeating the noun e.g. Julie liked her house. Her is a pronoun. It avoids having to say Julie liked Julie's house.

The correct forms showing possession are hers, his, theirs, ours, yours, its. There is no apostrophe.


Their books were expensive. Ours were cheaper.

Is this yours?

To show something is missing from a word/words

Sometimes, particularly in speech, words are shortened and may be joined. An apostrophe shows that a letter (or more than one letter) has been missed out.

In speech, very few people say do not. Most people say don't. Here the apostrophe is used to show that two words have been joined and a letter has been missed out.

Note. It is not usually acceptable in academic work to use the shortened form of words. You may, however, produce something for your course which is not in an academic style (e.g. creative writing, scripts, brochures). Check with your tutors if in such work you can use shortened forms of words, e.g. can't.


I can't believe it.
i.e. I cannot believe it. Here n and o have been missed out.

i.e. They are. Here a has been missed out.


It's means it is. The apostrophe means the second i has been missed out.

Its means of it. It is a pronoun, so where possession is shown it does not have an apostrophe.

It's always means it is. Its always means of it. They never mean anything else.


It's too late to go.
This means it is too late to go.

*Its too late to go.
This does not make sense. It means of it too late to go.

I bought one of its puppies.
This means I bought one of the puppies belonging to it.

*I bought one of it's puppies.
This does not make sense. It means I bought one of it is puppies.

If you always write it is in full rather than it's, you will not ever need to use an apostrophe in relation to its.

© Learning & Teaching Institute, Sheffield Hallam University 2004