Definition of "acid rock" []

• A style of rock music of the late 1960s having a prominent repetitive beat and lyrics that suggest psychedelic experiences. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "San Francisco groups had been producing acid rock for several years but by 1968 a few of these groups such as the Jefferson Airplane and the Grateful Dead became famous internationally while many others such as Daily Flash and Celestial Hysteria remained San Francisco acts."