What does "12:00 PM" actually mean (noon or midnight)?
Quick Answer: 12:00 PM means noon, the middle of the day. It’s when the clock switches from morning (AM) to afternoon (PM).
The 12-hour clock uses AM and PM to divide the day into two halves. AM stands for "ante meridiem," meaning before midday, and PM stands for "post meridiem," meaning after midday.
Since noon is the exact middle of the day, 12:00 PM marks that moment. Midnight is 12:00 AM, the start of a new day. This can feel confusing because 12 is both the end of one half and the start of another.