Learner's definition of YOURS
that which belongs to you
This book is yours. [=this book belongs to you; it is your book]
Yours is the book on the left. [=your book is the one on the left]
My car is old, but yours is older.
The responsibility for keeping the apartment clean is yours.
All those CDs of yours take up an awful lot of space.
Is that guy a friend of yours? [=your friend]
My wife is a big fan of yours.
— used at the end of an informal letter