Grammar Monster
Grammar Monster

An Apostrophe to Show Ownership (Grammar Lesson)

An Apostrophe to Show Ownership

An apostrophe and the letter s are used to show ownership.

When using an apostrophe for ownership, the first thing to consider is whether there is one owner (a singular owner) or more than one owner (a plural owner). This determines the position of the apostrophe. Here are some examples with the owners highlighted:
  • The boy's den.
  • (With one boy, the apostrophe is placed before the s. In other words, you have to add 's.)
  • The boys' den.
  • (With more than one boy, the apostrophe is placed after the s. In other words, add just '. Remember, the s will already be there.)

With a Singular Owner, the Apostrophe Is Placed before the S

When the owner is singular, add 's. For example:
  • Wagner's music is better than it sounds. (Mark Twain)
  • A friend's eye is a good mirror.

With a Plural Owner, the Apostrophe Is Placed after the S

When the owner is plural, add ' after the s. For example:
  • The dogs' dinner smells better than ours.
  • The ladies' mobile phones were confiscated until after the show.

Plural Nouns Not Ending S (Exception 1)

For plural words that do not end s (e.g., children, people, women), add 's (as though they were singular). For example:
  • Zeus does not bring all men's plans to fulfilment. (Homer, 800-700 BC)
  • All television is children's television. (Richard P. Adler)

Singular Nouns Ending S (Exception 2)

For singular words that end s (e.g., Dickens, series, Moses), add ' or 's. (You have a choice.) For example:
  • Wells's report was shockingly bad.
  • Wells' report was shockingly bad.
Useful guideline: Write it how you would say it. If you would say Wellsiz report, use Wells's. If you would say Wells report, use Wells'.

Compound Nouns (Exception 3)

For compound nouns (e.g., brother-in-law), add 's to the end regardless of whether it is singular or plural. For example:
  • My brother-in-law's help was essential.
  • (This is help from one brother-in-law.)
  • My brothers-in-law's help was essential.
  • (This is help from brothers-in-law, i.e., more than one brother-in-law.)
Read more about forming the plurals of compound nouns.

Apostrophes with Joint and Individual Ownership (A Quirk)

For joint ownership, make just the last word in the series possessive. For individual ownership, make all parts possessive. For example:
  • Peter and Paul's factories
  • (For joint ownership, only the last part is possessive.)

  • Peter's and Paul's factories
  • (For individual ownership, all parts are possessive.)
    (Without context, it will be assumed that Peter has one factory and Paul has one factory. Another construction is required if this is not the case: "Peter's factories and Paul's factories" is one option.)
Top Tip

It's Not about the Thing Being Owned

Where to put the apostrophe is only determined by the number of the owner. It doesn't matter whether the thing being owned is singular or plural.
  • dog's dinner
  • dogs' dinner
  • dog's dinners
  • dogs' dinners
In these examples, only the number of dogs is relevant. The number of dinners is irrelevant.

The Term Ownership Is Applied Very Loosely

Sometimes, the idea of ownership is very loosely applied. For example:
  • Picasso's painting
  • (These are paintings by Picasso.)
  • Men's changing rooms
  • (These are changing rooms for men.)
  • Two years' insurance
  • (This means insurance of two years. How can two years own insurance? Remember, the idea of ownership is often very loosely applied.)
Read about the possessive case for more about the function of the apostrophe for ownership.

It's Has Nothing To Do with Ownership

The word It's is a contraction of it is or it has.

It's has nothing to do with ownership. The word its (without an apostrophe) is used for ownership.
  • I saw its tail.
  • (The word its is used for possession.)
  • I know it's true.
  • (The contraction it's can always be expanded to it is or it has.)
Read more about it's and its.
Interactive Test


The History of the Possessive Apostrophe

The principal function of an apostrophe is to replace a missing letter (e.g., don't, isn't). This is related to the possessive apostrophe.

In old English, possession was shown by adding es to the possessor regardless of whether the possessor was singular or plural. For example:
  • cates dinner
  • catses dinner
  • menes dinner
Over time, the e was replaced by an apostrophe and if that left an ending of -s's, then the second s was removed.

This process still works for everything. There are no exceptions.

(1) Add es to the possessor
(2) Replace the e with '
(3) If left with s's, change to s'
Read more about using apostrophes.