Zen is a school of Mahāyāna Buddhism which originated in China during the 6th century CE as Chán. From China, Zen spread south to Vietnam, and east to Korea and Japan.
The word Zen is from the Japanese pronunciation of the Chinese word Chán (禪), which in turn is derived from the Sanskrit word dhyāna, which can be approximately translated as “absorption” or “meditative state”.
Zen emphasizes experiential wisdom in the attainment of enlightenment. As such, it de-emphasizes theoretical knowledge in favor of direct self-realization through meditation and dharma practice.