"lysergic acid diethylamide," 1950 (as LSD 25), from German LSD (1947), from letters in Lysergsäure-diäthylamid, the German form of the chemical name. For first element, see lysergic. German säure "acid" is cognate with English sour (adj.).
in reference to a crystalline organic compound, 1934, from the -lys- in hydrolysis (thus from Greek lysis "a loosening, a dissolution," from lyein "to loosen, dissolve;" from PIE root *leu- "to loosen, divide, cut apart") + the first syllable of ergot (a fungus from which the chemical was first obtained) + -ic.
Old English sur "sour, tart, acid, fermented," from Proto-Germanic *sura- "sour" (source also of Old Norse surr, Middle Dutch suur, Dutch zuur, Old High German sur, German sauer), from PIE root *suro- "sour, salty, bitter" (source also of Old Church Slavonic syru, Russian syroi "moist, raw;" Lithuanian sūras "salty," sūris "cheese").
Meaning "having a peevish disposition" is from early 13c. Sense in whisky sour (1885) is "with lemon added" (1862). Sour cream is attested from 1855. French sur "sour, tart" (12c.) is a Germanic loan-word.
1690s, from acid (adj.); originally loosely applied to any substance tasting like vinegar, in modern chemistry gradually given more precise definitions from early 18c. Slang meaning "LSD-25" first recorded 1966 (see LSD).
When I was on acid I would see things that looked like beams of light, and I would hear things that sounded an awful lot like car horns. [Mitch Hedberg, 1968-2005, U.S. stand-up comic]
Acid rock (type performed or received by people using LSD) is also from 1966; acid house dance music style is 1988, probably from acid in the hallucinogenic sense + house "dance club DJ music style."
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Harper, D. (n.d.). Etymology of LSD. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/LSD