Ortho- and peri-fused

{
  "id": "MLC-T-CHM-008335",
  "term": "Ortho- and peri-fused",
  "field": "Chemistry",
  "definition": "A polycyclic ring system in which one ring shares exactly two atoms, a single bond, with each of two or more other rings in a contiguous series, so that some atoms belong to three rings. Such a system has n shared bonds but fewer than 2n shared atoms, as in phenalene, whereas a purely ortho-fused system has exactly 2n.",
  "subject": "Organic and Biomolecular Chemistry",
  "references": [
    "Blue Book, p. 22 (https://www.acdlabs.com/iupac/nomenclature/)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/ortho-and-peri-fused/"
}