a.m or p.m.
Today we are learning Latin!
'ante' - means before
'post' - means past or after
'meridiem' - means midday
We use the abbreviations a.m. and p.m. when referring to a half of the day. So...
a.m. (ante meridiem) means before midday
p.m. (post meridiem) means after midday
Times from midnight to midday are recorded as a.m.
Times from midday to midnight are recorded as p.m.