Possessive Nouns

A possessive noun shows that something belongs to — or is directly connected to — someone or something. In English, the possessive is usually built with an apostrophe and the letter s attached to the owner.

In both sentences, the apostrophe marks the owner. Sarah's car means the car that belongs to Sarah; the dog's tail means the tail of the dog. The owner always comes first, and the thing owned comes right after.

The basic rule

For most singular nouns, add 's to the end.

The same rule works for names, job titles, animals, and even abstract concepts when they name a specific instance: Monday's meeting, the teacher's notes, the cat's food, today's deadline.

Singular nouns ending in s

Names like James, Chris, and Thomas already end in s. The modern standard is to still add 's, matching how the word is actually pronounced.

The older form — James', Jones' — is also accepted, especially in British writing and older textbooks. Both are correct; pick one style and stay consistent.

Plural nouns ending in s

Most plural nouns already end in s, so adding another s would be awkward. Instead, add only an apostrophe after the existing s.

The difference between singular and plural possessives is subtle in writing but important.

Irregular plurals

Some plural nouns do not end in s — words like children, men, women, people. These take the regular 's ending, just like singular nouns.

The rule is simple: if a plural already ends in s, add only an apostrophe; if it does not, add 's.

Joint vs individual ownership

When two people share one thing, only the last name takes the possessive form.

Tom and Anna live in one house together, so there is a single 's at the end.

When two people each own their own version of something, both names take the possessive form.

Here Tom has his car and Anna has hers — two separate cars. The word that follows is usually plural (cars, not car), which is a quick signal that the ownership is individual.

Time expressions

The possessive is also used with time and measurement, even though nothing is literally "owned". These phrases are fixed patterns and sound natural to native speakers.

The same logic as before applies: a day's (singular, 's), two weeks' (plural, apostrophe only).

Compound nouns

With hyphenated or multi-word nouns like mother-in-law or attorney general, the possessive ending attaches to the last word of the compound, never the first.

When to avoid the possessive

For most inanimate objects, English prefers the of-construction rather than an apostrophe.

However, the possessive form is perfectly normal in time expressions (today's paper, last year's results) and with certain vehicles and machines (the car's engine, the plane's wing). These are idiomatic exceptions that sound natural to the ear.

Common mistakes

Singular nouns

Plural nouns ending in -s

Irregular plurals

Joint vs individual ownership

Time expressions

Inanimate objects

Compound nouns