The recurring time frame for which employees are paid (weekly, biweekly, semi-monthly, monthly).
A pay period is the recurring timeframe for which employee hours are tracked and wages calculated. The four main types are Weekly (52 paychecks/year), Biweekly (26 paychecks/year — most common in the US), Semi-Monthly (24 paychecks/year — 1st and 15th), and Monthly (12 paychecks/year). The biweekly schedule results in two "three-paycheck months" per year, which is a great opportunity to boost savings.