The AM/PM system is a method of telling time that divides the 24-hour day into two 12-hour periods. The first period, from midnight to noon, is designated as AM, which stands for "ante meridiem," meaning "before midday." The second period, from noon to midnight, is designated as PM, which stands for "post meridiem," meaning "after midday." In this system, the hours are numbered from 1 to 12. For example, 1:00 AM is one hour after midnight, while 1:00 PM is one hour after noon. This format is commonly used in countries like the United States and Canada for everyday activities and scheduling.