1. Originally used in 1963 to mean mind-manifesting and now used by lay persons to describe some of the subjective aspects of intoxication, particularly with a drug; such as, lysergic acid diethylamide (LSD) or other drugs (hashish, mescaline, etc.) that are mind-altering and produce visual hallucinations.
2. Producing an effect or sensation held to resemble that produced by a psychedelic drug; specifically, having vivid colors, often in bold abstract designs or in motion.
3. A reference to a person who takes a psychedelic drug or who has a psychedelic life-style.