The word “Zen” comes from dhyana, a Sanskrit term for meditation. The various Buddhist schools we call Zen emphasize meditation more than the sutra study or devotional practices that characterize other schools of Buddhism
According to tradition, Zen comes from a long line of ancestors, starting with the Buddha, and was brought to China by the Indian monk Bodhidharma, the 27th ancestor in the lineage.
The Zen tradition developed in China in the 6th century, where it was known as Chan (the Chinese pronunciation of dhyana). There was strong mutual influence between Chan and Taoism. From China it went into Korea (where it was called Soen), from both Korea and China into Japan (where it was called Zen), and from China into Vietnam (where it was called Thien) — all of these names are local pronunciations of Chan. The first teachers of this tradition in America and Europe were from Japan, which is why we call it Zen.