A pay run is the term commonly used for payroll.

The run starts when you begin processing information to pay employees and ends when you fall into the swamp or trip and get devoured by monkeys.

Oh wait, I was thinking of a mobile game. Being devoured by monkeys does not tend to happen when processing payroll, but it does make your employees very happy, and with happy employees, you have a better chance of not being devoured.

The true pay run ends when your employees finally receive their checks, and you can take a break.