What is the collective noun for banknotes?

There isn't a commonly used, established collective noun for banknotes.

However, here are some options you could use, depending on the context:

Formal:

* A wad of banknotes

* A stack of banknotes

* A bundle of banknotes

* A sheaf of banknotes

Informal:

* A pile of cash

* A wad of dough

* A stack of bills

* A fistful of money

You could also use a collection of banknotes or a quantity of banknotes if you need something more neutral.

Ultimately, the best option will depend on the specific situation and the tone you want to convey.