This is the 6774th most frequent Chinese word.
氧气
Oxygen.
in the context of a natural process
植物通过光合作用产生氧气。
Plants produce oxygen through photosynthesis.
in the context of a survival tool
登山者携带氧气瓶以便在高海拔地区呼吸。
Mountaineers carry oxygen tanks to breathe at high altitudes.
in the context of describing a comforting presence