Zen is a school of Mahayana Buddhism[a] and originated in China during the 6th century CE as Chán. From China, Zen spread south to Vietnam, to Korea and east to Japan.[2]
The word Zen is derived from the Japanese pronunciation of the Middle Chinese word 禪 Dzyen (Modern Mandarin: Chán), which in turn is derived from the Sanskrit word dhyāna, which can be approximately translated as "absorption" or "meditative state".[3]
Zen emphasizes the attainment of enlightenment and the personal expression of direct insight in the Buddhist teachings.[4] As such, it de-emphasizes mere knowledge of sutras and doctrine[4][5] and favors direct understanding through zazen and interaction with an accomplished teacher.[6]
The teachings of Zen include various sources of Mahāyāna thought, especially Yogācāra, the Tathāgatagarbha Sutras and Huayan [7][8]. The Prajñāpāramitā literature[9] and, to a lesser extent, Madhyamaka have also been influential.

Source: Wikipedia