[Marsh.]

Originally Posted by y.winter

Right, but at the same time:
12 (noon) is exactly midday, so it's not exactly am or pm.
When 12 midnight can be classified by some people as after-midday and by some as before-midday.
It depends on how you look at it. I also refer to 12am as midnight and 12pm as noon, don't get me wrong, but when looking at the dry definition of pm and am, it can be arguable.

Not really.

00:00 is the start of a new day (am). Hence the clock resetting itself to 0.

12:00 is the start of the afternoon and is exactly halfway through the day (pm).