"black tar" meaning in English

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      "expansion": "black tar (uncountable)",
      "name": "en-noun"
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  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
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          "name": "Recreational drugs",
          "orig": "en:Recreational drugs",
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      "glosses": [
        "An illicit drug formed from the incomplete acetylation of morphine, containing a variable percentage of heroin."
      ],
      "id": "en-black_tar-en-noun-yHmN4UU8",
      "links": [
        [
          "illicit",
          "illicit"
        ],
        [
          "drug",
          "drug"
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        [
          "acetylation",
          "acetylation"
        ],
        [
          "morphine",
          "morphine"
        ],
        [
          "heroin",
          "heroin"
        ]
      ],
      "synonyms": [
        {
          "word": "brown"
        },
        {
          "word": "tar"
        }
      ],
      "tags": [
        "uncountable"
      ],
      "wikipedia": [
        "Black tar heroin"
      ]
    }
  ],
  "word": "black tar"
}

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      "expansion": "black tar (uncountable)",
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  "lang_code": "en",
  "pos": "noun",
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        "An illicit drug formed from the incomplete acetylation of morphine, containing a variable percentage of heroin."
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          "illicit",
          "illicit"
        ],
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          "drug",
          "drug"
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        [
          "acetylation",
          "acetylation"
        ],
        [
          "morphine",
          "morphine"
        ],
        [
          "heroin",
          "heroin"
        ]
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      "tags": [
        "uncountable"
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      "wikipedia": [
        "Black tar heroin"
      ]
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  "synonyms": [
    {
      "word": "brown"
    },
    {
      "word": "tar"
    }
  ],
  "word": "black tar"
}