"quaternary twin" meaning in English

{
  "forms": [
    {
      "form": "quaternary twins",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "quaternary twin (plural quaternary twins)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "2024 March 18, Rachel Abrahamson, Today:",
          "text": "Quaternary twins occur when one set of identical twins has children with another set of identical twins",
          "type": "quote"
        }
      ],
      "glosses": [
        "First cousins whose parents are a pair of identical twins."
      ],
      "id": "en-quaternary_twin-en-noun-bI7MdMul",
      "links": [
        [
          "First cousins",
          "first cousin"
        ],
        [
          "identical twin",
          "identical twin"
        ]
      ]
    }
  ],
  "word": "quaternary twin"
}

{
  "forms": [
    {
      "form": "quaternary twins",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "quaternary twin (plural quaternary twins)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with quotations",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "examples": [
        {
          "ref": "2024 March 18, Rachel Abrahamson, Today:",
          "text": "Quaternary twins occur when one set of identical twins has children with another set of identical twins",
          "type": "quote"
        }
      ],
      "glosses": [
        "First cousins whose parents are a pair of identical twins."
      ],
      "links": [
        [
          "First cousins",
          "first cousin"
        ],
        [
          "identical twin",
          "identical twin"
        ]
      ]
    }
  ],
  "word": "quaternary twin"
}