Absolute instrument

{
  "id": "MLC-T-MET-003184",
  "term": "Absolute instrument",
  "field": "Meteorology and atmospheric science",
  "definition": "A measuring device that determines the value of a physical quantity directly from its fundamental properties, without requiring calibration against another standard. An example is a primary standard barometer, which measures pressure based on the height of a mercury column. These instruments are used to establish and verify other measurement standards.",
  "see_also": [
    "secondary instrument"
  ],
  "url": "https://mlchart.com/terminology/meteorology/absolute-instrument/"
}