psychedelic

1 of 2

noun

psy·​che·​del·​ic ˌsī-kə-ˈde-lik 

: a psychedelic drug (such as LSD)

psychedelic

2 of 2

adjective

1

a

: of, relating to, or being drugs (such as LSD) capable of producing abnormal psychic effects (such as hallucinations) and sometimes psychotic states

b

: produced by or associated with the use of psychedelic drugs

a psychedelic experience

2

: imitating, suggestive of, or reproducing effects (such as distorted or bizarre images or sounds) resembling those produced by psychedelic drugs

psychedelic color schemes

3

: of, relating to, characteristic of, or being the period of the mid- to late-1960s that is associated with the psychedelic drug culture

psychedelic rock

the psychedelic era/movement

… the "rainbow newspaper" of San Francisco that burst onto the psychedelic scene in 1966 …

—Don Lattin

… speaking of stereotypes, the illustrations reject any hint of a '60s psychedelic style …

—Steven Heller

psychedelically

ˌsī-kə-ˈde-li-k(ə-)lē 

adverb

Did you know?

The most famous—or notorious—of the psychedelic drugs is LSD, a synthetic compound that is usually created in a lab but can also be derived from alkaloids found in some fungi. The other well-known psychedelics are psilocybin (likewise obtained from fungi) and mescaline (obtained from peyote cactus). How psychedelics produce their effects is still fairly mysterious, partly because research ceased for almost 20 years because of their reputation, but scientists are determined to find the answers and much research is now under way. Psychedelics are now used to treat anxiety in patients with cancer, and are being tested in the treatment of such serious conditions as severe depression, alcoholism, and drug addiction.

Examples of psychedelic in a Sentence

Recent Examples on the Web

Noun

Where Prozac and similar drugs slowly change the chemicals in the brain, psychedelics may quickly prompt neurons to create new connections. — Angelica Peebles, CNBC, 16 July 2026

Its companies research therapeutic psychedelics and treatments for premature ejaculation. — Zach Helfand, New Yorker, 13 July 2026

Adjective

Since leaving the band the War on Drugs, in 2008, Vile has become a solo avatar for psychedelic guitar music, his rich catalogue easygoing and nonchalant, but also sprawling. — Hilton Als, New Yorker, 17 July 2026

The theory is that psychedelic drugs relax strongly held but inappropriate negative beliefs and, in combination with therapy, allow patients to form truer ones. — Tom Chivers, semafor.com, 17 July 2026

Word History

Etymology

Noun

irregular from psych- + Greek dēloun to show, from dēlos evident; akin to Sanskrit dīdeti it shines, Latin dies day — more at deity

First Known Use

Noun

1956, in the meaning defined above

Adjective

1957, in the meaning defined at sense 1a

Phrases Containing psychedelic

• pre-psychedelic

Rhymes for psychedelic

• philatelic
• allelic
• angelic
• relic
• telic

Kids Definition

psychedelic

1 of 2 adjective

psy·​che·​del·​ic ˌsī-kə-ˈdel-ik 

1

: of, relating to, or being a drug (as LSD) that produces abnormal often extreme mental effects (as hallucinations)

2

a

: imitating the effects of psychedelic drugs

b

: glowing brightly

psychedelic

2 of 2 noun

: a psychedelic drug

Medical Definition

psychedelic

1 of 2 noun

psy·​che·​del·​ic ˌsī-kə-ˈdel-ik 

: a psychedelic drug (as LSD)

psychedelic

2 of 2 adjective

1

: of, relating to, or being drugs (as LSD) capable of producing abnormal psychic effects (as hallucinations) and sometimes psychotic states

2

: produced by or associated with the use of psychedelic drugs

a psychedelic experience

psychedelically

-ˈdel-i-k(ə-)lē 

adverb