Interesting question! Time is very important!
The West has:
a.m.: ante meridiem, before noon
p.m.: post meridiem, after noon
(meridiem: accusative of meridies "midday, noon")
A day, divided into 2 halves, each on 1 side of noon. Observed from the point of midday, ante is what was, post is what will be. The sun waxes, the sun wanes.
Also in Chinese:
上午 = 午夜 到 中午
下午 = 中午 到 午夜
‘上早’这个词不存在。‘上早’是什么意思？'earlier than early'? 午夜？？
'上晚‘这个词不存在。‘上晚’是什么意思？'earlier than evening'? 午后？？
The character 午 seems to be a picture of a big hammer used to husk rice. How did that come to be midday? Maybe, in ancient China, people did this at noon, so they could eat? 有人知道？
Of course, if you are a photon (光子）all this is unimportant, you are completely timeless!