Enso (circle) is a sacred symbol in the Zen school of Buddhism and is one of the most common subjects of Japanese calligraphy, even though it is a symbol and not a character. You may hear it called the Circle of Enlightenment, the Infinity Circle and even the Lost Symbol of Reiki. If you actually took the meanings of the two Kanji symbols that make up the word, enso would translate as Mutual Circle or Circle of Togetherness.
