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

Psychedelics such as ibogaine, ayahuasca, psilocybin, LSD and MDMA have all shown promising results in treating mental health conditions including PTSD, traumatic brain injury and treatment-resistant depression. —Clara Harter, Los Angeles Times, 26 June 2025

Now imagine that level of technical sophistication on LSD in the mid-70s. —Noah Eckstein, HollywoodReporter, 23 June 2025

One of Willy’s notable Harvard stories involved taking a psychology class from Timothy Leary, along with his classmate Ted Kaczynski, in which Willy and the sixteen-year-old future Unabomber voluntarily participated in Leary’s early experiments with LSD. —Benjamin Hale june 23, Literary Hub, 23 June 2025

In Switzerland, using LSD, MDMA, and psilocybin in medicine has been legal since 2014, for both research and treatment of mental health conditions. —Chad De Guzman, Time, 18 June 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