The psychedelic is a concept the name of which is derived from the Ancient Greek words psychē (ψυχή, "soul") and dēloun (δηλοῦν, "to make visible, to reveal"), translating to "mind-revealing".

Related phenomena include:

Psychedelic drug (also known as a psychedelic substance or simply a psychedelic), a psychoactive drug whose primary action is to alter cognition and perception, such as LSD, psilocybin mushrooms, mescaline or DMT, but sometimes also cannabis and MDMA
Psychedelic experience, a temporary altered state of consciousness induced by the consumption of psychedelic drugs
Psychedelic art, art inspired by the psychedelic experience
Psychedelia, a subculture surrounding the psychedelic experience, based on appreciation of psychedelic art and the use of psychedelic drugs
Psychedelic music, popular music influenced by psychedelia, aiming to replicate or enhance the psychedelic experience
Psychedelic rock, originating in the mid-1960s
Psychedelic folk, originating in the late 1960s and early 1970s
Psychedelic pop, which combines pop music with influences from psychedelic rock and psychedelic folk
Psychedelic soul, which combines soul music with influences from psychedelic rock
Psychedelic trance (also known as psytrance or simply psy), an electronic music style originating in the late 1990s
Psychedelic era, a time of social, musical and artistic change related to psychedelia (from the early 1960s to the mid-1970s)
Psychedelic literature, literature related to psychedelic drugs and the psychedelic experience
Psychedelic film, a film genre influenced by psychedelia and the psychedelic experience
Psychedelic therapy, therapeutic practices involving the use of psychedelic drugs, primarily to assist psychotherapy