Oxygen

{
  "id": "MLC-T-MET-007769",
  "term": "Oxygen",
  "field": "Meteorology and atmospheric science",
  "definition": "A chemical element with the symbol O and atomic number 8, existing in the atmosphere primarily as a diatomic molecule (O2). It constitutes approximately 21% of the Earth's atmosphere by volume and is a product of photosynthesis. While O2 is relatively unreactive in the lower atmosphere, its photodissociation in the stratosphere by ultraviolet radiation produces atomic oxygen (O), which then reacts with O2 to form ozone (O3).",
  "url": "https://mlchart.com/terminology/meteorology/oxygen/"
}