Possessive nouns are nouns which possess something; i.e. they have something. Of course, the thing the noun possesses is another noun. You can identify a possessive noun by the apostrophe; most nouns show the possessive with an apostrophe and an s.
The cat’s toy was missing.
The cat possesses the toy, and we denote this by use of ‑‘s at the end of cat.
Is this Brandon’s book?
I pulled a feather from the goose’s tail.
When a noun ends in the letter s or an s sound, the same format often applies. This is a matter of style, however, and some style guides suggest leaving off the extra s.
I have been invited to the boss’s house for dinner.
The trainer flipped a fish into the walrus’s open mouth.
Some plural nouns end in an s that sounds like a z. In these cases, we just add an apostrophe.
All of the Joneses’ tickets will be held for pickup during the family reunion.
Be careful when you take the bees’ honey from the hives.