[psy.che.del.ic] n [irreg. fr. psych- + Gk deloun to show, fr. delos evident; akin to Skt dideti it shines, L dies day--more at deity] (1956): a psychedelic drug (as LSD)
[2]psychedelic adj (1957) 1 a: of, relating to, or being drugs (as LSD) capable of producing abnormal psychic effects (as hallucinations) and sometimes psychic states resembling mental illness b: produced by or associated with the use of psychedelic drugs "a ~ experience"
2: imitating, suggestive of, or reproducing effects (as distorted or bizarre images or sounds) resembling those produced by psychedelic drugs "~ color schemes" -- psy.che.del.i.cal.ly adv