"llyfrothen adeiniog" meaning in Welsh

{
  "forms": [
    {
      "form": "llyfrothod adeiniog",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "f",
        "2": "llyfrothod adeiniog"
      },
      "expansion": "llyfrothen adeiniog f (plural llyfrothod adeiniog)",
      "name": "cy-noun"
    }
  ],
  "lang": "Welsh",
  "lang_code": "cy",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Welsh entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "lifeform",
          "langcode": "cy",
          "name": "Blennies",
          "orig": "cy:Blennies",
          "parents": [
            "Fish",
            "Vertebrates",
            "Chordates",
            "Animals",
            "Lifeforms",
            "All topics",
            "Life",
            "Fundamental",
            "Nature"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "butterfly blenny (Blennius ocellaris)"
      ],
      "id": "en-llyfrothen_adeiniog-cy-noun-oGkxPJ6y",
      "tags": [
        "feminine"
      ]
    }
  ],
  "word": "llyfrothen adeiniog"
}

{
  "forms": [
    {
      "form": "llyfrothod adeiniog",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "f",
        "2": "llyfrothod adeiniog"
      },
      "expansion": "llyfrothen adeiniog f (plural llyfrothod adeiniog)",
      "name": "cy-noun"
    }
  ],
  "lang": "Welsh",
  "lang_code": "cy",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "Entries missing English vernacular names of taxa",
        "Entries using missing taxonomic name (species)",
        "Pages with 1 entry",
        "Pages with entries",
        "Welsh countable nouns",
        "Welsh entries with incorrect language header",
        "Welsh feminine nouns",
        "Welsh lemmas",
        "Welsh multiword terms",
        "Welsh nouns",
        "Welsh nouns with red links in their headword lines",
        "cy:Blennies"
      ],
      "glosses": [
        "butterfly blenny (Blennius ocellaris)"
      ],
      "tags": [
        "feminine"
      ]
    }
  ],
  "word": "llyfrothen adeiniog"
}