Ante-meridian and post meridian
pt
OX
AK
The Russian Federation is abbreviated R.F.
Read-Only-Memory
MSGT= Master Sergeant
Glomerular filtration rate
The ounce = oz, from the old Italian word onza which is now spelt oncia
Midnight to noon is 12 hours (AM), noon to midnight is another 12 hours (PM). Therefore, it is 12 hours from PM to AM.
It's neither, 12 noon and 12 midnight are just that although there are a lot of illiterates in positions where they should know better!)
it is pm. when it gets to noon, it is pm
12 pm, 1 pm, 2 pm, 3 pm, 4 pm, 5 pm, 6 pm, 7 pm, 8 pm. 8 hours.