a music festival, held over three days in 1969 near the town of Woodstock in New York State, where about 500,000 young people went to see rock, pop, and folk singers and bands, such as Janis Joplin, Jimi Hendrix, Jefferson Airplane, and The Who. It is famous especially for the hippies who attended it, and people see it as a very typical example of the hippie culture.
Definition from the Longman Dictionary of Contemporary English Advanced Learner's Dictionary.