Etymology From Ancient Greek ψυχή (psukhḗ, “mind, soul”) + δῆλος (dêlos, “manifest, visible”) + English -ic (prefix forming adjectives with the sense ‘of or pertaining to’), coined by the English psychiatrist Humphry Osmond (1917–2004) in a 1956 letter to Aldous Huxley.
1
Of, containing, generating, or reminiscent of drug-induced altered awareness, distortions of perception, hallucinations, etc.
With those drugs has come the psychedelic philosophy, an impassioned belief in the self-revealing, mind-expanding powers of potent weeds and seeds and chemical compounds known to man since prehistory but wholly alien to the rationale of Western society.1967, Joe David Brown, editor, The Hippies, New York: Time, Inc, page 2:
2
Of graphics, etc.: having abstract shapes, bright colours, etc., reminiscent of drug-induced distortions of perception or hallucinations.
There was a woman sitting on the edge of his bed. She had coral-orange hair, beryl-blue eyes, arched brows, freckles, a coy smile, a psychedelic labcoat and she was, he suddenly realized, his best friend of over twenty years.2022 September 24, HarryBlank, “Transition”, in SCP Foundation, archived from the original on 23 May 2024:
Etymology From Ancient Greek ψυχή (psukhḗ, “mind, soul”) + δῆλος (dêlos, “manifest, visible”) + English -ic (prefix forming adjectives with the sense ‘of or pertaining to’), coined by the English psychiatrist Humphry Osmond (1917–2004) in a 1956 letter to Aldous Huxley.
1
Any psychoactive substance (such as LSD or psilocybin) which, when consumed, causes perceptual changes (sometimes erratic and uncontrollable), visual hallucination, and altered awareness of the body and mind.
I was going to become a three-drug connection to all my friends, psychedelics, hash and pot.2006, Dean McCormick, Dead End Street, page 62: