Learn one Chinese Character a day - 下

We have learnt 上, Then to your best guess, what would be the meaning of 下, whose Oracle Script is ? Before revealing the answer, let us examine its evolution history first: (image taken from http://vividict.com/)

evolution history of 下

that is right, 下 is the opposite of 上. To refer back to explanation of 上, please visit https://xiongzou.blogspot.sg/2017/10/learn-one-chinese-character-day.html

For 上 has the meaning of "upward or above or up", 下 thus has the meaning of downward or below or down. For example 向下.

For 上 has meaning of "on, on top of, upon and etc", 下 thus has the meaning of below, beneath or under, for example 下面.
For 上 has meaning of "superior", 下 thus has the meaning of subordinate. For example 下属.

For 上 has meaning of "preceding, previous or last", 下 thus has the meaning of following, next or subsequent. For example 下次.

For 上 has the meaning of "go up", thus 下 has the meaning of "go down". for example 下楼. 

下, as a very frequently used Chinese character, has still many other subtle meanings besides what we listed above, however they are a good starting point for us to know what 下 means.

Now let us enjoy a Chinese calligraphy with 下 inside:

听雨读简书，灯下著文章。

And with understanding of 上 and 下, can you guess what could be the meaning of 卡？