"compound of oxygen with another element," 1790, from French oxide (1787), coined by French chemists Louis-Bernard Guyton de Morveau and Antoine Lavoisier from ox(ygène) (see oxygen) + (ac)ide "acid" (see acid (n.)).
gaseous chemical element, 1790, from French oxygène, coined in 1777 by French chemist Antoine-Laurent Lavoisier (1743-1794), from Greek oxys "sharp, acid" (from PIE root *ak- "be sharp, rise (out) to a point, pierce") + French -gène "something that produces" (from Greek -genes "formation, creation;" see -gen).
Intended to mean "acidifying (principle)," it was a Greeking of French principe acidifiant. So called because oxygen was then considered essential in the formation of acids (it is now known not to be). The element was isolated by Priestley (1774), who, using the old model of chemistry, called it dephlogisticated air. The downfall of the phlogiston theory required a new name, which Lavoisier provided. Oxygen-mask is attested from 1912.
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."