The possessive pronoun their shows ownership for two or more people.
The house belongs to my parents. The house is their house.
This dog belongs to my cousins. The dog is their dog.
The boat belongs to Sam and Sue. It is their boat.
Use the word their in front of a noun to show ownership of that object. their house, their dog, their boat
The pronoun theirs is used in place of a noun
Our parents own the house. The house is theirs.
My cousins own the dog. The dog is theirs.
Sam and Sue own the boat. The boat is theirs.
The words their and theirs are both used to show ownership. Use their along with a noun. Theirs takes the place of a noun.
▶Now you try it. Choose either their or theirs for the blank in this sentence: Janet and Bill won the contest, so the prize is _______. Did you find the pronoun that fits best? Good for you!