Fertile land between two rivers is called Doab.
There are four doabs of Pakistan:
1. Sindh Sagar Doab: Between river Indus and Jhelum
2. Chaj Doab: Between river Chenab and Jhelum
3. Rachna Doab: Between river Ravi and Chenab
4. Bari Doab: Between river Beas and Ravi