Clock in Definition 1 of 2Pro Tip 1/3Workplace Routine Used to signify starting work, often with a timecard or digital system. I clock in at the factory using the punch card machine. Pro Tip 2/3Time Management Reflects an employee's punctuality and is used by employers to track work hours. She was commended for always clocking in right at 8 am. Pro Tip 3/3Company Policy Often mandatory, and failing to do so may lead to payroll issues or disciplinary action. I got a warning for forgetting to clock in last week.