"Ethniu" meaning in Old Irish

{
  "descendants": [
    {
      "lang": "Irish",
      "lang_code": "ga",
      "word": "Eithne"
    },
    {
      "descendants": [
        {
          "lang": "Icelandic",
          "lang_code": "is",
          "word": "Eðna"
        }
      ],
      "lang": "Old Norse",
      "lang_code": "non",
      "raw_tags": [
        "borrowed"
      ],
      "word": "Eðna"
    },
    {
      "lang": "Scottish Gaelic",
      "lang_code": "gd",
      "word": "Eithne"
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "sga",
        "2": "proper noun",
        "g": "f"
      },
      "expansion": "Ethniu f",
      "name": "head"
    }
  ],
  "lang": "Old Irish",
  "lang_code": "sga",
  "pos": "name",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Old Irish entries with incorrect language header",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 2 entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "langcode": "sga",
          "name": "Individuals",
          "orig": "sga:Individuals",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "langcode": "sga",
          "name": "Irish mythology",
          "orig": "sga:Irish mythology",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "The daughter of the Fomorian king Balor, wife of Cían and the mother of Lug and Delbáeth, and the grandmother of Cú Chulainn and Finn mac Cumail."
      ],
      "id": "en-Ethniu-sga-name-Bw8ZYcFV",
      "links": [
        [
          "Irish",
          "Irish"
        ],
        [
          "mythology",
          "mythology"
        ],
        [
          "Fomorian",
          "Fomorian"
        ],
        [
          "Balor",
          "Balor"
        ],
        [
          "Cían",
          "Cían#Old_Irish"
        ],
        [
          "Lug",
          "Lug#Old_Irish"
        ],
        [
          "Delbáeth",
          "Delbáeth#Old_Irish"
        ],
        [
          "Cú Chulainn",
          "Cú Chulainn#Old_Irish"
        ],
        [
          "Finn mac Cumail",
          "Finn mac Cumail#Old_Irish"
        ]
      ],
      "raw_glosses": [
        "(Irish mythology) The daughter of the Fomorian king Balor, wife of Cían and the mother of Lug and Delbáeth, and the grandmother of Cú Chulainn and Finn mac Cumail."
      ],
      "tags": [
        "Irish",
        "feminine"
      ],
      "topics": [
        "human-sciences",
        "mysticism",
        "mythology",
        "philosophy",
        "sciences"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ˈeθʲ.nʲu/"
    }
  ],
  "word": "Ethniu"
}

{
  "descendants": [
    {
      "lang": "Irish",
      "lang_code": "ga",
      "word": "Eithne"
    },
    {
      "descendants": [
        {
          "lang": "Icelandic",
          "lang_code": "is",
          "word": "Eðna"
        }
      ],
      "lang": "Old Norse",
      "lang_code": "non",
      "raw_tags": [
        "borrowed"
      ],
      "word": "Eðna"
    },
    {
      "lang": "Scottish Gaelic",
      "lang_code": "gd",
      "word": "Eithne"
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "sga",
        "2": "proper noun",
        "g": "f"
      },
      "expansion": "Ethniu f",
      "name": "head"
    }
  ],
  "lang": "Old Irish",
  "lang_code": "sga",
  "pos": "name",
  "senses": [
    {
      "categories": [
        "Old Irish entries with incorrect language header",
        "Old Irish feminine nouns",
        "Old Irish lemmas",
        "Old Irish proper nouns",
        "Old Irish terms with IPA pronunciation",
        "Pages with 2 entries",
        "Pages with entries",
        "sga:Individuals",
        "sga:Irish mythology"
      ],
      "glosses": [
        "The daughter of the Fomorian king Balor, wife of Cían and the mother of Lug and Delbáeth, and the grandmother of Cú Chulainn and Finn mac Cumail."
      ],
      "links": [
        [
          "Irish",
          "Irish"
        ],
        [
          "mythology",
          "mythology"
        ],
        [
          "Fomorian",
          "Fomorian"
        ],
        [
          "Balor",
          "Balor"
        ],
        [
          "Cían",
          "Cían#Old_Irish"
        ],
        [
          "Lug",
          "Lug#Old_Irish"
        ],
        [
          "Delbáeth",
          "Delbáeth#Old_Irish"
        ],
        [
          "Cú Chulainn",
          "Cú Chulainn#Old_Irish"
        ],
        [
          "Finn mac Cumail",
          "Finn mac Cumail#Old_Irish"
        ]
      ],
      "raw_glosses": [
        "(Irish mythology) The daughter of the Fomorian king Balor, wife of Cían and the mother of Lug and Delbáeth, and the grandmother of Cú Chulainn and Finn mac Cumail."
      ],
      "tags": [
        "Irish",
        "feminine"
      ],
      "topics": [
        "human-sciences",
        "mysticism",
        "mythology",
        "philosophy",
        "sciences"
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "/ˈeθʲ.nʲu/"
    }
  ],
  "word": "Ethniu"
}