What Is Their Main Difference?
The difference between 'ours' and 'us' lies in their different parts of speech which is the categories into which words are divided according to their grammar. For example noun, verb, adjective, etc.
'Ours' is the possessive form of the subject pronoun 'we'. It shows that which belongs to us. We do not place a noun after it. It always stands alone.
These are Mandy's books.
'Ours' is the possessive pronoun replacing the phrase 'our books' to avoid repetition.
These books are
'Us' is the object pronoun, and it is used when we are the object of a verb or preposition. We also use 'us' after the verb 'be' to introduce or identify ourselves (especially on the phone or at the door).
Come on, open the door. It's
Are They Interchangeable?
So, the pronoun 'ours' and 'us' are not interchangeable. One (ours) is a possessive pronoun that always comes alone. And the other (us) is an object pronoun.
The books on this shelf are