"Congo red" meaning in English

{
  "forms": [
    {
      "form": "Congo reds",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "~"
      },
      "expansion": "Congo red (countable and uncountable, plural Congo reds)",
      "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"
        },
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          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Dyes",
          "orig": "en:Dyes",
          "parents": [
            "Matter",
            "Pigments",
            "Chemistry",
            "Nature",
            "Colors",
            "Sciences",
            "All topics",
            "Light",
            "Vision",
            "Fundamental",
            "Energy",
            "Senses",
            "Perception",
            "Body"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A dye that turns red in alkaline, blue in acidic solutions."
      ],
      "id": "en-Congo_red-en-noun-fezNBaUK",
      "links": [
        [
          "dye",
          "dye"
        ],
        [
          "alkaline",
          "alkaline"
        ],
        [
          "acidic",
          "acidic"
        ],
        [
          "solution",
          "solution"
        ]
      ],
      "related": [
        {
          "word": "Congo dye"
        },
        {
          "word": "Congo group"
        }
      ],
      "tags": [
        "countable",
        "uncountable"
      ],
      "wikipedia": [
        "Congo red"
      ]
    }
  ],
  "word": "Congo red"
}

{
  "forms": [
    {
      "form": "Congo reds",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "~"
      },
      "expansion": "Congo red (countable and uncountable, plural Congo reds)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "Congo dye"
    },
    {
      "word": "Congo group"
    }
  ],
  "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:Dyes"
      ],
      "glosses": [
        "A dye that turns red in alkaline, blue in acidic solutions."
      ],
      "links": [
        [
          "dye",
          "dye"
        ],
        [
          "alkaline",
          "alkaline"
        ],
        [
          "acidic",
          "acidic"
        ],
        [
          "solution",
          "solution"
        ]
      ],
      "tags": [
        "countable",
        "uncountable"
      ],
      "wikipedia": [
        "Congo red"
      ]
    }
  ],
  "word": "Congo red"
}