a nonmetallic bivalent element that is normally a colorless odorless tasteless nonflammable diatomic gas; constitutes 21 percent of the atmosphere by volume; the most abundant element in the earth's crust
"The diver held her breath to avoid using up all the oxygen before surfacing."
The chemical element (symbol O) with an atomic number of 8 and relative atomic mass of 15.9994. It is a colorless and odorless gas.
"The lab technician carefully sealed the jar to prevent any air, including oxygen, from contaminating the pure sample they were analyzing."
In plain English: Oxygen is the gas you breathe that helps your body turn food into energy.
"We breathe in oxygen to stay alive."
Usage: Use oxygen to refer to the specific chemical element or the breathable gas essential for life, not as a general term for air. Avoid using it to describe other gases like nitrogen or carbon dioxide, even though they are components of the atmosphere.
The word comes from French oxygène, which was coined by Lavoisier from Ancient Greek words meaning "sharp" and "birth." It originally referred to oxygen's supposed role as an acid-forming principle.