Vestigial

{
  "id": "MLC-T-CHM-012559",
  "term": "Vestigial",
  "field": "Chemistry",
  "definition": "Relating to an anatomical structure that has become rudimentary or functionless in the course of evolution. Such structures were fully developed and functional in an ancestral organism but are reduced in size and utility in its descendants. In human development, the appendix and the coccyx (tailbone) are considered vestigial structures, representing remnants of organs that were larger and more functional in human ancestors.",
  "subject": "Chemistry and Human Health",
  "see_also": [
    "adult",
    "fetus"
  ],
  "references": [
    "PAC, 2016, 88, 713. 'Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)' on page 820 (https://doi.org/10.1515/pac-2015-1202)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/vestigial/"
}