"blwch llythyrau" meaning in Welsh

{
  "forms": [
    {
      "form": "blychau llythyrau",
      "tags": [
        "plural"
      ]
    },
    {
      "form": "no-table-tags",
      "source": "mutation",
      "tags": [
        "table-tags"
      ]
    },
    {
      "form": "cy-mut",
      "source": "mutation",
      "tags": [
        "inflection-template"
      ]
    },
    {
      "form": "blwch llythyrau",
      "source": "mutation",
      "tags": [
        "error-unrecognized-form"
      ]
    },
    {
      "form": "flwch llythyrau",
      "source": "mutation",
      "tags": [
        "soft"
      ]
    },
    {
      "form": "mlwch llythyrau",
      "source": "mutation",
      "tags": [
        "error-unrecognized-form"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m",
        "2": "blychau llythyrau",
        "head": "blwch llythyrau"
      },
      "expansion": "blwch llythyrau m (plural blychau llythyrau)",
      "name": "cy-noun"
    }
  ],
  "inflection_templates": [
    {
      "args": {},
      "name": "cy-mut"
    }
  ],
  "lang": "Welsh",
  "lang_code": "cy",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "_dis": "50 50",
          "kind": "topical",
          "langcode": "cy",
          "name": "Post",
          "orig": "cy:Post",
          "parents": [
            "Communication",
            "All topics",
            "Fundamental"
          ],
          "source": "w+disamb"
        }
      ],
      "glosses": [
        "letterbox (receptacle for receiving post)"
      ],
      "id": "en-blwch_llythyrau-cy-noun-H3EJV8eC",
      "links": [
        [
          "letterbox",
          "letterbox"
        ]
      ],
      "tags": [
        "masculine"
      ]
    },
    {
      "categories": [
        {
          "_dis": "10 90",
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w+disamb"
        },
        {
          "_dis": "5 95",
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w+disamb"
        },
        {
          "_dis": "14 86",
          "kind": "other",
          "name": "Welsh entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w+disamb"
        },
        {
          "_dis": "50 50",
          "kind": "topical",
          "langcode": "cy",
          "name": "Post",
          "orig": "cy:Post",
          "parents": [
            "Communication",
            "All topics",
            "Fundamental"
          ],
          "source": "w+disamb"
        }
      ],
      "glosses": [
        "letterbox, post box, pillar box (receptacle for collecting post to be delivered)"
      ],
      "id": "en-blwch_llythyrau-cy-noun-009ApOiX",
      "links": [
        [
          "letterbox",
          "letterbox"
        ],
        [
          "post box",
          "post box"
        ],
        [
          "pillar box",
          "pillar box"
        ]
      ],
      "synonyms": [
        {
          "word": "bocs postio"
        }
      ],
      "tags": [
        "masculine"
      ]
    }
  ],
  "word": "blwch llythyrau"
}

{
  "categories": [
    "Pages with 1 entry",
    "Pages with entries",
    "Welsh countable nouns",
    "Welsh entries with incorrect language header",
    "Welsh lemmas",
    "Welsh masculine nouns",
    "Welsh multiword terms",
    "Welsh nouns",
    "Welsh nouns with red links in their headword lines",
    "cy:Post"
  ],
  "forms": [
    {
      "form": "blychau llythyrau",
      "tags": [
        "plural"
      ]
    },
    {
      "form": "no-table-tags",
      "source": "mutation",
      "tags": [
        "table-tags"
      ]
    },
    {
      "form": "cy-mut",
      "source": "mutation",
      "tags": [
        "inflection-template"
      ]
    },
    {
      "form": "blwch llythyrau",
      "source": "mutation",
      "tags": [
        "error-unrecognized-form"
      ]
    },
    {
      "form": "flwch llythyrau",
      "source": "mutation",
      "tags": [
        "soft"
      ]
    },
    {
      "form": "mlwch llythyrau",
      "source": "mutation",
      "tags": [
        "error-unrecognized-form"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m",
        "2": "blychau llythyrau",
        "head": "blwch llythyrau"
      },
      "expansion": "blwch llythyrau m (plural blychau llythyrau)",
      "name": "cy-noun"
    }
  ],
  "inflection_templates": [
    {
      "args": {},
      "name": "cy-mut"
    }
  ],
  "lang": "Welsh",
  "lang_code": "cy",
  "pos": "noun",
  "senses": [
    {
      "glosses": [
        "letterbox (receptacle for receiving post)"
      ],
      "links": [
        [
          "letterbox",
          "letterbox"
        ]
      ],
      "tags": [
        "masculine"
      ]
    },
    {
      "glosses": [
        "letterbox, post box, pillar box (receptacle for collecting post to be delivered)"
      ],
      "links": [
        [
          "letterbox",
          "letterbox"
        ],
        [
          "post box",
          "post box"
        ],
        [
          "pillar box",
          "pillar box"
        ]
      ],
      "synonyms": [
        {
          "word": "bocs postio"
        }
      ],
      "tags": [
        "masculine"
      ]
    }
  ],
  "word": "blwch llythyrau"
}