"darning wool" meaning in English

{
  "forms": [
    {
      "form": "darning wools",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "~"
      },
      "expansion": "darning wool (countable and uncountable, plural darning wools)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "wool, typically wound on a card former, that is used to make small repairs"
      ],
      "id": "en-darning_wool-en-noun-L4AQ7uwy",
      "links": [
        [
          "wool",
          "wool"
        ],
        [
          "repair",
          "repair"
        ]
      ],
      "synonyms": [
        {
          "word": "mending wool"
        }
      ],
      "tags": [
        "countable",
        "uncountable"
      ]
    }
  ],
  "word": "darning wool"
}

{
  "forms": [
    {
      "form": "darning wools",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "~"
      },
      "expansion": "darning wool (countable and uncountable, plural darning wools)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English uncountable nouns"
      ],
      "glosses": [
        "wool, typically wound on a card former, that is used to make small repairs"
      ],
      "links": [
        [
          "wool",
          "wool"
        ],
        [
          "repair",
          "repair"
        ]
      ],
      "tags": [
        "countable",
        "uncountable"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "mending wool"
    }
  ],
  "word": "darning wool"
}