This module introduces possessives using an apostrophe + “s” in English. Possessives sometimes omit the “s,” which is covered here, too.

Plural vs. Possessive ‘S’

The misuse of the possessive -s is a grammatical error that plagues all sorts of writers. The possessive -s is most commonly misused when a writer confuses it with the plural form. Fortunately, the rules governing the usage of the possessive -s and the plural form are quite clear cut and logical.

Noun Plurals

The most common way to pluralize a noun is to simply add an -s at the end.

Hamburger (singular) becomes hamburgers (plural) College (singular) becomes colleges (plural)

Nouns that end in a vowel followed by a -y take an -s in the plural.

Monkey (singular) becomes monkeys (plural)

Nouns that end in a consonant followed by a -y undergo a more dramatic change. First, the -y changes to an -ie and then an -s is added.

Baby (singular) becomes babies (plural)

Nouns that end in a sibilant (s, x, z, ch, sh) pluralize by adding an -es.

Church (singular) becomes churches (plural)

Nouns that end in an -is are replaced by -es in the plural.

Thesis (singular) becomes theses (plural)

Count nouns that end in -f pluralize by changing to a -ves.

Calf (singular) becomes calves (plural)

Nouns that end in -o preceded by a vowel usually pluralize by adding an -s. Nouns that end in -o preceded by a consonant usually pluralize with an -es. The nouns that do not follow this pattern are often words imported from other languages and take their plural form according to the rules of that language.

Soprano (singular) becomes Sopranos (plural)

The Possessive

The possessive -s is used to show belonging: Kevin’s coat

But, belonging can be less obvious: A good night’s sleep

The possessive forms of nouns are formed by adding an apostrophe and in most cases the possessive -s. When in doubt about whether or not your phrase requires the possessive, tum it around and see if it breaks down into an “of the” statement.

The doctor’s stethoscope- The stethoscope of the doctor- Correct

Three days’ grace- The grace of three days- Correct

The doctors’ running the clinic- The running the clinic of the doctors – Incorrect To place the apostrophe:

Add an ‘s to the singular forms of a noun, even if it ends in an -s.

The principal’s office Mrs. Jones’s garden party

You have the tools. We help you use them.

Add an ‘s to the plural forms of nouns that do not end in -s.

The children’s bedroom

Add an ‘ to the plural forms of nouns that end in -s.

The addicts’ support group

The seven Von Trapp kids’ singing nanny

Apostrophes and Possessive Pronouns

Apostrophes should not be used with possessive pronouns (my, yours, hers, his, its, ours). These pronouns do not need apostrophes because they inherently show possession.

Incorrect: his’ speech                        Correct: his speech

Incorrect: that bike is your’s             Correct: that bike is yours

The most complicated possessive pronoun is “its”. Its and it’s do not serve the same grammatical function. It’s is a contraction for “it is” and its is the possessive pronoun that signifies “belonging to it”. Check if you’re using “it’s” correctly by asking yourself whether you could replace “it’s” with “it is” and still have your sentence make sense. Remember, you do not use an apostrophe with the other possessive pronouns in the third person singular, his and hers, so do not use it with its!

Using Its / It’s

Hint: If you can say “it is,” then use the contraction.

E.g. The dog wagged its tail makes no sense if you say “the dog wagged it is tail,” so don’t use an apostrophe.

Whereas

Its going to rain later today does make sense if you say “it is going to rain later today,” so use the apostrophe:

It’s going to rain later today.