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 -genēs "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.

1971, contracted from the chemical name, amino-p-hydroxybenzylpenicillin; see amino- + oxy- + penicillin.

1919, from dioxy-, word-forming element in chemistry indicating the presence of two oxygen atoms or two additional oxygen atoms (see di- (1) + oxy-) + chemical suffix -in (2). All the compounds in the group are characterized by two oxygen atoms.

active principle of the thyroid gland, 1915, from thyro-, combining form of thyroid, + oxy- (apparently a reference to the oxygen atom present in it, but OED has it as a shortening of oxy-indol) + chemical suffix -ine (2), denoting an amino acid.

Proto-Indo-European root meaning "be sharp, rise (out) to a point, pierce."

It might form all or part of: acacia; acanthus; accipiter; acer; acerbic; acerbity; acervate; acervulus; acescent; acetic; acid; acicular; acme; acne; acrid; acridity; acrimony; acro-; acrobat; acromegaly; acronym; acrophobia; acropolis; acrostic; acrylic; acuity; aculeate; acumen; acupressure; acupuncture; acute; aglet; ague; Akron; anoxic; awn; coelacanth; dioxin; deoxy-; eager; ear (n.2) "grain part of corn;" edge (n.); egg (v.) "to goad on, incite;" eglantine; epoxy; ester; exacerbation; hammer; hypoxia; mediocre; oxalic; oxide; oxy-; oxygen; oxymoron; paragon; pyracanth; paroxysm; selvage; vinegar.

It might also be the source of: Greek akros "at the end, at the top, outermost; consummate, excellent," akis "sharp point," akē "point of an iron tool," akantha "thorn," akmē "summit, edge," oxys "sharp, bitter;" Sanskrit acri- "corner, edge," acani- "point of an arrow," asrih "edge;" Oscan akrid (ablative singular) "sharply;" Latin acer (fem. acris) "sharp to the senses, pungent, bitter, eager, fierce," acutus "sharp, pointed," acuere "to sharpen," acerbus "harsh, bitter," acere "be sharp, be bitter," acus "a needle, pin," ocris "jagged mountain;" Lithuanian ašmuo "sharpness," akstis "sharp stick;" Old Lithuanian aštras, Lithuanian aštrus "sharp;" Old Church Slavonic ostru, Russian óstryj "sharp;" Old Irish er "high;" Welsh ochr "edge, corner, border;" Old Norse eggja "goad;" Old English ecg "sword;" German Eck "corner."