Difference between AM and PM

If you live in the united states,canada, or Australia, you use a 12 hour system for telling time.
If you look at this clock it is 7 oclock. However is this 7 oclock in the morning or 7 oclock at night. This is where am and pm help
.The 12-hour system divides the 24 hours of a day into two periods lasting 12 hours each. The first 12-hour period is designated as am. It runs from midnight to noon. The second period, marked pm, covers the 12 hours from noon to midnight.
AM comes from the latin phrase ante meridiem, which translates to, before midday)
and p.m. from the Latin phrase post meridiem which translates to, past midday
There are 24 hours in a day, this requires the hour hand to pass the 12 twice.