The possessive case is used to show ownership or a relationship between things. We form it using an apostrophe (').
Singular Nouns
To make a singular noun possessive, simply add an apostrophe + s ('s) to the end of the word.
- The dog's collar is blue. (The collar belongs to one dog.)
- Sarah's laptop is on the table.
- The car's engine is making a strange noise.
If a singular noun already ends in s (like James or boss), you usually still add 's.
- James's car is very fast.
- My boss's office is down the hall.
Plural Nouns
If the noun is plural and already ends in s (like boys or teachers), you just add an apostrophe (') at the end. Do NOT add an extra "s".
- The boys' treehouse is huge. (The treehouse belongs to multiple boys.)
- The teachers' lounge is closed today.
However, if the plural noun is irregular and does NOT end in "s" (like men, women, children), you must add 's.
- The children's toys are everywhere.
- Where is the women's restroom?
Joint vs. Separate Ownership
When two people own something together, only put the apostrophe on the final name:
- Ben and Jerry's ice cream is delicious. (They own the same company.)
When two people own things separately, put the apostrophe on both names:
- Ben's and Jerry's cars are both parked outside. (They own two different cars.)