A company's payroll is a complete list of everyone who works there and how much money they make. The small coffee shop where you work might have just four employees on its payroll.
Any business or organization with a paid staff has a payroll. A school's payroll might include the principal, teachers, office workers, school nurse, and maintenance workers, for example. You can also use the term payroll for the entire amount of money that a company pays its workers over the course of a year, or for the department that calculates these salaries and hands out paychecks.