AM is ante meridian and PM is post meridian. It's referenced to the prime meridian through Greenwich UK. If the sun is to the east of the line (ie. Before noon where it is vertical) it's before (ante) the meridian. If it's after (post) noon it's after the meridian. It's all outdated but that's how time works.

[–] KISSmyOSFeddit@lemmy.world 7 points 5 months ago (4 children)

12 pm isn't past noon, it's noon.
12 am is past noon just as much as it is before noon.
So for 12 o'clock, choosing am or pm is arbitrary convention.
So it would make more sense to reverse them, to get a consistant row that starts with 1:
1 am, 2 am, 3 am, 4 am, 5 am, 6 am, 7 am, 8 am, 9 am, 10 am, 11 am, 12 am, 1 pm , 2 pm , 3 pm , 4 pm , 5 pm , 6 pm , 7 pm , 8 pm , 9 pm , 10 pm , 11 pm , 12 pm

[–] BearGun@ttrpg.network 15 points 5 months ago

Except that you don't just use it for whole hours. 12.01 is clearly post meridian, so it has to be PM if you wanna keep the meaning. With your example 12 am and 12.01 pm would either be one minute apart or you'd have to drop the whole meaning of am and pm, which would just make it an entirely arbitrary construct that's even more difficult to understand.

On the other hand, as a European I'm quite happy with 24h time keeping. This whole am-pm system is quite unnecessary.

[–] ChanSecodina@sh.itjust.works 12 points 5 months ago

Not to defend 12hr time because it’s dumb as a bag of bricks, but 12:45pm is definitely past noon and having the time go from 12:00am to 12:01pm would be way too silly. Also, you can think of the moment between 11:59:59.999999~ as just before noon and 12:00:00.0000000001 as the first fraction of a second after noon if it helps.

[–] itslilith@lemmy.blahaj.zone 8 points 5 months ago

The US loves systems of measurement that make no sense

[–] Hugh_Jeggs@lemm.ee 4 points 5 months ago

Away and don't talk pish. Ok, 12pm sounds a bit odd, but it would be even more odd to say 12.05pm, 12.59pm then jump to 1am