"dyer's woad" meaning in English

{
  "forms": [
    {
      "form": "dyer's woads",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "~"
      },
      "expansion": "dyer's woad (countable and uncountable, plural dyer's woads)",
      "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"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "lifeform",
          "langcode": "en",
          "name": "Crucifers",
          "orig": "en:Crucifers",
          "parents": [
            "Brassicales order plants",
            "Plants",
            "Lifeforms",
            "All topics",
            "Life",
            "Fundamental",
            "Nature"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A plant of species Isatis tinctoria, which is the source of the blue dye woad used in the Middle Ages, before being replaced as source by Indigofera tinctoria."
      ],
      "id": "en-dyer's_woad-en-noun-J01FAM9I",
      "links": [
        [
          "Isatis tinctoria",
          "Isatis tinctoria#Translingual"
        ],
        [
          "woad",
          "woad"
        ],
        [
          "Indigofera tinctoria",
          "Indigofera tinctoria#Translingual"
        ]
      ],
      "related": [
        {
          "word": "indigo"
        }
      ],
      "synonyms": [
        {
          "sense": "Isatis tinctoria",
          "word": "woad"
        },
        {
          "sense": "Isatis tinctoria",
          "word": "glastrum"
        },
        {
          "sense": "Isatis tinctoria",
          "word": "asp of Jerusalem"
        }
      ],
      "tags": [
        "countable",
        "uncountable"
      ]
    }
  ],
  "word": "dyer's woad"
}

{
  "forms": [
    {
      "form": "dyer's woads",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "~"
      },
      "expansion": "dyer's woad (countable and uncountable, plural dyer's woads)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "indigo"
    }
  ],
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English uncountable nouns",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Crucifers"
      ],
      "glosses": [
        "A plant of species Isatis tinctoria, which is the source of the blue dye woad used in the Middle Ages, before being replaced as source by Indigofera tinctoria."
      ],
      "links": [
        [
          "Isatis tinctoria",
          "Isatis tinctoria#Translingual"
        ],
        [
          "woad",
          "woad"
        ],
        [
          "Indigofera tinctoria",
          "Indigofera tinctoria#Translingual"
        ]
      ],
      "tags": [
        "countable",
        "uncountable"
      ]
    }
  ],
  "synonyms": [
    {
      "sense": "Isatis tinctoria",
      "word": "woad"
    },
    {
      "sense": "Isatis tinctoria",
      "word": "glastrum"
    },
    {
      "sense": "Isatis tinctoria",
      "word": "asp of Jerusalem"
    }
  ],
  "word": "dyer's woad"
}