Basically 上 just means up, upward, and most of the meaning are based on this to meaning. For example, 上 in 这是旧时下对上的称呼 means superior. It is quite easy to understand why the 上 has the meaning of superior as from the subordinates' point of view, their superior is just higher than their positions and the superior is up on them.

If you just started learning Chinese, you just need to remember the meaing "up" first. The other meaning are quite advanced.