The 12-hour clock is a timekeeping system that divides the day into two 12-hour periods. The first period runs from midnight to noon, labeled as AM, while the second period spans from noon to midnight, labeled as PM. Each hour is numbered from 1 to 12, making it easy to read and understand. In this system, the hours repeat every 12 hours. For example, 1:00 AM is followed by 1:00 PM. This format is commonly used in everyday life, especially in countries like the United States and Canada, where it is preferred over the 24-hour clock system.