"n-iarthur" meaning in Middle Irish

{
  "head_templates": [
    {
      "args": {
        "1": "mga",
        "2": "mutated noun"
      },
      "expansion": "n-iarthur",
      "name": "head"
    }
  ],
  "lang": "Middle Irish",
  "lang_code": "mga",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "extra": "eclipsed form of iarthur",
          "word": "n-íarthur"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "Middle Irish entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "Alternative spelling of n-íarthur: eclipsed form of iarthur."
      ],
      "id": "en-n-iarthur-mga-noun-0zUyfEyH",
      "links": [
        [
          "n-íarthur",
          "n-íarthur#Middle Irish"
        ],
        [
          "iarthur",
          "iarthur#Middle Irish"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative"
      ]
    }
  ],
  "word": "n-iarthur"
}

{
  "head_templates": [
    {
      "args": {
        "1": "mga",
        "2": "mutated noun"
      },
      "expansion": "n-iarthur",
      "name": "head"
    }
  ],
  "lang": "Middle Irish",
  "lang_code": "mga",
  "pos": "noun",
  "senses": [
    {
      "alt_of": [
        {
          "extra": "eclipsed form of iarthur",
          "word": "n-íarthur"
        }
      ],
      "categories": [
        "Middle Irish eclipsed forms",
        "Middle Irish entries with incorrect language header",
        "Middle Irish mutated nouns",
        "Middle Irish non-lemma forms"
      ],
      "glosses": [
        "Alternative spelling of n-íarthur: eclipsed form of iarthur."
      ],
      "links": [
        [
          "n-íarthur",
          "n-íarthur#Middle Irish"
        ],
        [
          "iarthur",
          "iarthur#Middle Irish"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative"
      ]
    }
  ],
  "word": "n-iarthur"
}