The story
The album The Psychedelic Sounds of the 13th Floor Elevators (1966) first used psychedelic to describe music; the band The 13th Floor Elevators is sometimes credited with coining the term.
Etymology from Wiktionary, CC BY-SA 4.0.
psychedelic rock
Today it means: A genre of rock music influenced by psychedelia, blues, electronic music, folk music, jazz, and the hippie counterculture of the 1960s. Full definition →