〇 in Chinese / Japanese...

〇 is the famous Enso symbol, which you will see widely used by Japanese Zen Buddhists.

In a twist, I am starting to see Enso used more and more by Chinese Buddhists.

Here is the typical appearance of Enso artwork by Japanese calligrapher Kougetsu.

Enso is not a Japanese Kanji character. It falls more into the category of a symbol. There is some debate, but many consider Enso to be a religious symbol.

Some call this “The Circle of Enlightenment.” Others call it the “Infinity Circle.” If you actually took the meanings of the two Kanji (円相) that make up the word “En-so,” you could read it as “Mutual Circle” or “Circle of Togetherness.” I think the Enso symbol can simply mean different things to different people. Therefore, you should let it have the meaning that you perceive.

The appearance of your Enso will be determined by the artist's personal style, feeling, mood, etc.

零 is the number zero in Chinese, Japanese Kanji, and old Korean Hanja.

零 is a strange selection for a wall scroll, so it's here mostly for reference. I guess it's OK if zero is important to you.

Note: In modern Japan and China, they will often just write a circle to represent zero in lieu of this character.