What is the meaning of possessive noun?

Answer 1

A possessive noun is a noun indicating ownership or possession. For example 'the story of the witness' can be turned into 'the witness's story'.
The possessive is shown by adding an 's to the end of a noun or just an ' after plural nouns already ending in -s. Examples:

• the car of my mother = my mother's car
• the teacher of our class = our class'steacher
• the coats of the children = the children'scoats
• the covers of the books = the books'covers
• the meeting of the bosses = the bosses'meeting

A possessive noun can also indicate origin or purpose. Examples:

• The ladies' room does not belong to ladies, it means that it is designated for the use of ladies.
• A store that sells men's suits doesn't sell suits that belong to some men, it sells suits for men.
• A book of Shakespeare's plays are not plays that belong to Mr. Shakespeare, they are plays written by him.

Additional examples:

• John's bicycle is new. (the bicycle belongs to John)
  
• The cookies were made from grandma's recipe. (the recipe from grandma)
  
• The girls' room needs straightening up. (the room of the girls)
  
• Take this bucket to the horses' barn. (the barn for the horses)
  

Answer 2

A possessive noun indicates ownership or possession of a person, place, thing, or idea. It is formed by adding an apostrophe and "s" to the noun. For example, "Sarah's book" shows that the book belongs to Sarah.