LSD

noun

ˌel-(ˌ)es-ˈdē 

: a semisynthetic illicit organic compound C₂₀H₂₅N₃O derived from ergot that induces extreme sensory distortions, altered perceptions of reality, and intense emotional states, that may also produce delusions or paranoia, and that may sometimes cause panic reactions in response to the effects experienced

called also lysergic acid diethylamide

Examples of LSD in a Sentence

Recent Examples on the Web

With the Dead, Weir was part of Ken Kesey’s Acid Tests in the mid-’60s, centered around experiments with LSD, and the band’s members were known to use nitrous oxide, marijuana, speed and heroin. —Erin Osmon, Los Angeles Times, 11 Jan. 2026

Marijuana previously was labeled a Schedule 1 drug under Drug Enforcement Administration (DEA) regulations, the same category the agency uses for drugs like heroin, ecstasy and LSD. —Ashley J. Dimella, FOXNews.com, 10 Jan. 2026

Haploclastus devamatha or the psychedelic earth tiger, Indian rainbow tarantula, or LSD earth tiger is only found in the tropical forests of the southern Western Ghats in Kerala, India. —Laura Baisas, Popular Science, 7 Jan. 2026

Ever since the Controlled Substances Act was signed into law in 1970, federal regulators have grouped cannabis together with some of the most restricted drugs in America, such as heroin and LSD. —Hannah Parker, NBC news, 24 Dec. 2025

Word History

Etymology

borrowed from German, from Lysergsäure-Diäthylamid "lysergic acid diethylamide"

First Known Use

1950, in the meaning defined above

Kids Definition

LSD

noun

ˌel-ˌes-ˈdē 

: an illegal drug that causes abnormal sensations, extreme and changeable states of emotion, unnatural changes in the way time and space are experienced, and hallucinations and that may sometimes cause panic in response to the effects experienced

Medical Definition

LSD

noun

ˌel-ˌes-ˈdē 

: a semisynthetic illicit organic compound C₂₀H₂₅N₃O derived from ergot that induces extreme sensory distortions, altered perceptions of reality, and intense emotional states, that may also produce delusions or paranoia, and that may sometimes cause panic reactions in response to the effects experienced

called also acid, lysergic acid diethylamide, lysergide