"regnal number" meaning in English

{
  "forms": [
    {
      "form": "regnal numbers",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "regnal number (plural regnal numbers)",
      "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"
        }
      ],
      "examples": [
        {
          "ref": "2011, Norman Davies, Vanished Kingdoms, Penguin, published 2012, page 429",
          "text": "Umberto I, who had fought at Solferino, had been christened with the name of the dynasty's founder, and changed his regnal number from IV to I.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "An ordinal number that distinguishes a monarch from others of the same name."
      ],
      "id": "en-regnal_number-en-noun-9uAAAS3l",
      "links": [
        [
          "ordinal number",
          "ordinal number"
        ],
        [
          "distinguish",
          "distinguish"
        ],
        [
          "monarch",
          "monarch"
        ],
        [
          "name",
          "name"
        ]
      ]
    }
  ],
  "word": "regnal number"
}

{
  "forms": [
    {
      "form": "regnal numbers",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "regnal number (plural regnal numbers)",
      "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",
        "Quotation templates to be cleaned"
      ],
      "examples": [
        {
          "ref": "2011, Norman Davies, Vanished Kingdoms, Penguin, published 2012, page 429",
          "text": "Umberto I, who had fought at Solferino, had been christened with the name of the dynasty's founder, and changed his regnal number from IV to I.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "An ordinal number that distinguishes a monarch from others of the same name."
      ],
      "links": [
        [
          "ordinal number",
          "ordinal number"
        ],
        [
          "distinguish",
          "distinguish"
        ],
        [
          "monarch",
          "monarch"
        ],
        [
          "name",
          "name"
        ]
      ]
    }
  ],
  "word": "regnal number"
}