n. Chem. a colourless tasteless odourless gaseous element, occurring naturally in air, water, and most minerals and organic substances, and essential to plant and animal life.
Usage:
Symb.: O.
Phrases and idioms:
oxygen mask a mask placed over the nose and mouth to supply oxygen for breathing. oxygen tent a tentlike enclosure supplying a patient with air rich in oxygen.
Derivatives:
oxygenous adj.
Etymology: F oxyg{egrave}ne acidifying principle (as OXY- 2): it was at first held to be the essential principle in the formation of acids