oxygen
noun [ U ] uk/ˈɒk.sɪ.dʒən/ us/ˈɑːk.sɪ.dʒən/ (symbol O)
B2 氧，氧气
a chemical element that is a gas with no smell or colour. Oxygen forms a large part of the air on earth, and is needed by animals and plants to live.
- More examples
- Air is composed mainly of nitrogen and oxygen.
- Deep-sea divers carry cylinders of oxygen on their backs.
- Mountain climbers use oxygen when they reach higher altitudes.
- Plants are the main source of atmospheric oxygen.
- The symbol for oxygen is O2.