The term "psychedelic" was coined by LSD researcher Humphry Osmond in a letter to author Aldous Huxley in the mid-1950s. They were searching for a word to describe the effects of mind-altering chemicals such as LSD and mescaline. It is important to bear these origins in mind when considering the concept of psychedelic music.

Psychedelic culture became known among the general populace in 1966-67 thanks to efforts of advocates like Timothy Leary and the Beatles. The first media use of the word "psychedelic" in connection with rock music occurred in February 1966 in an Austin newspaper article on the 13th Floor Elevators, who also had it on their business cards.

More on the embryonic days of the mid-1960s can be found in the timeline of early psychedelia.

At the end of the 1960s the term had become watered down and misused by media and marketing people. "Psychedelic" could mean anything that was exotic or counterculture. This misconception lingers to this day, when 1960s artists like Frank Zappa or Velvet Underground are often incorrectly called "psychedelic". One goal of these pages is to restore the original meaning of psychedelic music, which is music that is related to the LSD (and comparable hallucinogens) experience.