What does 9:00 PM stand for?

Understanding 9:00 PM and the 12-Hour Clock

When you see 9:00 PM on a clock, it refers to nine o'clock in the evening. This notation is part of the standard 12-hour time system, which splits the twenty-four hours of a day into two equal halves of twelve hours each.

The abbreviation PM stands for the Latin phrase Post Meridiem, which translates directly to "after midday" or "after noon." This period begins right at 12:00 noon and runs all the way until 11:59 at night, marking the second half of the calendar day before the cycle resets at midnight.