English Reference
noun

LSD

n.
US /ˌɛˌɫɛsˈdi/ lsd

  1. 01 B2 Upper Intermediate

    Stands for Lysergic Acid Diethylamide. A powerful drug that makes people see or hear things that are not real.

    Abbreviation for Lysergic Acid Diethylamide. A potent synthetic crystalline compound that causes hallucinations and sensory distortions.

    Simple

    The musician admitted that he had experimented with LSD during the 1960s.

    In context

    Clinical researchers are currently investigating whether microdoses of LSD can effectively treat chronic depression and anxiety disorders.

  2. 02 C1 Advanced British EnglishArchaic

    Stands for pounds, shillings, and pence. This was the system of money used in the UK before 1971.

    Abbreviation for Librae, Solidi, Denarii. The pre-decimal currency system of the United Kingdom, consisting of pounds, shillings, and pence.

    Simple

    My grandfather still remembers how to calculate prices in LSD from before the change.

    In context

    The transition from the LSD system to decimalisation in 1971 represented a significant cultural shift for the British public.

    Usage

    Usually written as £sd or l.s.d. in historical documents.

    pounds, shillings, and pence
  3. 03 C2 Proficiency Technical Science

    Stands for longshore drift. This is the way waves move sand and stones along a beach.

    Abbreviation for longshore drift. The geological process by which sediments such as sand or pebbles are transported along a coastline.

    Simple

    The new sea wall was built to stop LSD from washing away the beach.

    In context

    Coastal engineers must account for the rate of LSD when designing groynes to prevent significant beach erosion.

    longshore drift
  4. 04 C2 Proficiency Technical Technical

    Stands for limited-slip differential. A part in a car that helps the wheels turn better on slippery roads.

    Abbreviation for limited-slip differential. A mechanism in a vehicle that allows two output shafts to rotate at different speeds while limiting the maximum difference.

    Simple

    The sports car comes with an LSD to improve handling in tight corners.

    In context

    Off-road enthusiasts often prefer a mechanical LSD over electronic systems for better traction on uneven terrain.

    limited slip differential

University of California, Davis, researchers have stripped down LSD to the base features responsible for its hallucinogenic and therapeutic effects.

Phys.org· 7 Sept 2026

Much of the focus had been on LSD, psilocybin and ketamine, but 5-MeO-DMT provided a whole new level of experience.

The Guardian· 17 Aug 2026

Etymology 1

From Latin lībra solidus dēnārius.

Etymology 2

From German LSD, initialism of Lysergsäure-diethylamid.

Etymology 3

Other initialisms.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin Latin lībra solidus dēnārius
Level C1 · Advanced
Frequency Frequent
Updated