"ystlum du" meaning in Welsh

{
  "forms": [
    {
      "form": "ystlumod du",
      "tags": [
        "plural"
      ]
    },
    {
      "form": "ystlumod duon",
      "tags": [
        "plural"
      ]
    },
    {
      "form": "no-table-tags",
      "source": "mutation",
      "tags": [
        "table-tags"
      ]
    },
    {
      "form": "cy-mut",
      "source": "mutation",
      "tags": [
        "inflection-template"
      ]
    },
    {
      "form": "ystlum du",
      "source": "mutation",
      "tags": [
        "error-unrecognized-form"
      ]
    },
    {
      "form": "hystlum du",
      "source": "mutation",
      "tags": [
        "prothesis-h"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m",
        "2": "ystlumod du",
        "pl2": "ystlumod duon"
      },
      "expansion": "ystlum du m (plural ystlumod du or ystlumod duon)",
      "name": "cy-noun"
    }
  ],
  "inflection_templates": [
    {
      "args": {},
      "name": "cy-mut"
    }
  ],
  "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": "Bats",
          "orig": "cy:Bats",
          "parents": [
            "Mammals",
            "Vertebrates",
            "Chordates",
            "Animals",
            "Lifeforms",
            "All topics",
            "Life",
            "Fundamental",
            "Nature"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "western barbastelle (Barbastella barbastellus)"
      ],
      "id": "en-ystlum_du-cy-noun-05Ytlkb~",
      "links": [
        [
          "barbastelle",
          "barbastelle"
        ],
        [
          "Cymdeithas Edward Llwyd",
          "w:Cymdeithas Edward Llwyd"
        ],
        [
          "Y Lolfa",
          "w:Y Lolfa"
        ]
      ],
      "tags": [
        "masculine"
      ]
    }
  ],
  "word": "ystlum du"
}

{
  "forms": [
    {
      "form": "ystlumod du",
      "tags": [
        "plural"
      ]
    },
    {
      "form": "ystlumod duon",
      "tags": [
        "plural"
      ]
    },
    {
      "form": "no-table-tags",
      "source": "mutation",
      "tags": [
        "table-tags"
      ]
    },
    {
      "form": "cy-mut",
      "source": "mutation",
      "tags": [
        "inflection-template"
      ]
    },
    {
      "form": "ystlum du",
      "source": "mutation",
      "tags": [
        "error-unrecognized-form"
      ]
    },
    {
      "form": "hystlum du",
      "source": "mutation",
      "tags": [
        "prothesis-h"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m",
        "2": "ystlumod du",
        "pl2": "ystlumod duon"
      },
      "expansion": "ystlum du m (plural ystlumod du or ystlumod duon)",
      "name": "cy-noun"
    }
  ],
  "inflection_templates": [
    {
      "args": {},
      "name": "cy-mut"
    }
  ],
  "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 lemmas",
        "Welsh masculine nouns",
        "Welsh multiword terms",
        "Welsh nouns",
        "Welsh nouns with red links in their headword lines",
        "cy:Bats"
      ],
      "glosses": [
        "western barbastelle (Barbastella barbastellus)"
      ],
      "links": [
        [
          "barbastelle",
          "barbastelle"
        ],
        [
          "Cymdeithas Edward Llwyd",
          "w:Cymdeithas Edward Llwyd"
        ],
        [
          "Y Lolfa",
          "w:Y Lolfa"
        ]
      ],
      "tags": [
        "masculine"
      ]
    }
  ],
  "word": "ystlum du"
}

{
  "called_from": "form_descriptions/1089",
  "msg": "suspicious unhandled suffix in Welsh: 'ystlum du', originally 'ystlum du m'",
  "path": [
    "ystlum du"
  ],
  "section": "Welsh",
  "subsection": "noun",
  "title": "ystlum du",
  "trace": ""
}

{
  "called_from": "form_descriptions/1089",
  "msg": "suspicious unhandled suffix in Welsh: 'ystlum du', originally 'ystlum du m'",
  "path": [
    "ystlum du"
  ],
  "section": "Welsh",
  "subsection": "noun",
  "title": "ystlum du",
  "trace": ""
}

{
  "called_from": "form_descriptions/1089",
  "msg": "suspicious unhandled suffix in Welsh: 'ystlumod du', originally 'ystlumod du'",
  "path": [
    "ystlum du"
  ],
  "section": "Welsh",
  "subsection": "noun",
  "title": "ystlum du",
  "trace": ""
}

{
  "called_from": "inflection/865",
  "msg": "inflection table: IF WITHOUT ELSE EVALS False: ystlum du/Welsh 'radical' base_tags=set()",
  "path": [
    "ystlum du"
  ],
  "section": "Welsh",
  "subsection": "noun",
  "title": "ystlum du",
  "trace": ""
}

{
  "called_from": "inflection/865",
  "msg": "inflection table: IF WITHOUT ELSE EVALS False: ystlum du/Welsh 'nasal' base_tags={'soft', 'error-unrecognized-form'}",
  "path": [
    "ystlum du"
  ],
  "section": "Welsh",
  "subsection": "noun",
  "title": "ystlum du",
  "trace": ""
}