Per mille

{
  "id": "MLC-T-MET-007840",
  "term": "Per mille",
  "field": "Meteorology and atmospheric science",
  "definition": "A unit of measurement meaning 'per thousand,' denoted by the symbol ‰. It expresses a ratio as parts per thousand, similar to how percent means parts per hundred. In atmospheric science, it is sometimes used to describe small concentrations or variations, such as isotopic ratios in water vapor or atmospheric gases.",
  "url": "https://mlchart.com/terminology/meteorology/per-mille/"
}