An oriental school of Mahayana Buddhism, that maintains awareness, enlightenment, and a higher perception can be achieved through meditation, self-contemplation and intuition, rather than through sacred texts or scriptures. Within these schools, the subjects develop awareness and enlightenment using many different techniques. These practices are at the heart of Zen.
Zen and Zen Buddhism are one and the same thing.
References:
Heinrich Dumoulin, History of Zen Buddhism; Sohaku Ogata, Zen for the
West (1959 & 1973); Nancy W. Ross, The World of Zen (1960); Alan
Watts, The Spirit of Zen (1958); D.T. Suzuki, Essays in Zen Buddhism
(London: Rider, 1970); D.T. Suzuki, Introduction to Zen Buddhism
(London: Rider, 1969).