Descartes ray

{
  "id": "MLC-T-MET-004940",
  "term": "Descartes ray",
  "field": "Meteorology and atmospheric science",
  "definition": "A specific light ray that contributes to the formation of a rainbow, undergoing one internal reflection within a spherical water droplet. This ray exits the droplet at the minimum angle of deviation relative to the incident light, concentrating light at that angle. The phenomenon was first explained by René Descartes in the 17th century.",
  "url": "https://mlchart.com/terminology/meteorology/descartes-ray/"
}