Real Dictionary

oxygen in American English
a colorless, odorless, tasteless, gaseous chemical element that occurs free in the atmosphere, forming one fifth of its volume, and in combination in water, sandstone, limestone, etc.: it is very active, combines with nearly all other elements, is the mos
noun: a colorless, odorless, gaseous element constituting about one-fifth of the volume of the atmosphere and present in a combined state in nature. It is the supporter of combustion in air and was the standard of atomic, combining, and molecular weights until

oxygen in British English
noun: a colourless odourless highly reactive gaseous element: the most abundant element in the earth's crust (49.2 per cent). It is essential for aerobic respiration and almost all combustion and is widely used in industry. Symbol: O; atomic no: 8; atomic wt: 1