if someone is on the payroll of a company, they are employed by that company:
The company now has 350 people on the payroll.
the activity of managing salary payments for workers in a company:
the payroll department
a computerized payroll system
3 [uncountable and countable]BEWBBC
the total amount of wages paid to all the people working in a particular company or industry:
the annual payroll was $88 million