What is the common expression for shah

"Shah" itself is already a common expression, but if you're looking for alternative ways to refer to a Shah, here are some options:

Formal:

* His Imperial Majesty (used for the Shah of Persia)

* His Majesty

* The King (This can be used, but remember that "Shah" is a specific title used for Persian rulers)

Informal:

* The ruler

* The king of Persia (again, only accurate for the historical Shahs of Persia)

Other options:

* The sovereign (This is a more general term for any ruler)

Ultimately, the best way to refer to a Shah depends on the specific context and your desired level of formality.