"one-drop rule" meaning in English

{
  "forms": [
    {
      "form": "the one-drop rule",
      "tags": [
        "canonical"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "noun",
        "head": "the one-drop rule"
      },
      "expansion": "the one-drop rule",
      "name": "head"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "American English",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English entries with topic categories using raw markup",
          "parents": [
            "Entries with topic categories using raw markup",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English terms with non-redundant non-automated sortkeys",
          "parents": [
            "Terms with non-redundant non-automated sortkeys",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Racism",
          "orig": "en:Racism",
          "parents": [
            "Forms of discrimination",
            "Discrimination",
            "Society",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "derived": [
        {
          "word": "reverse one-drop rule"
        }
      ],
      "examples": [
        {
          "ref": "2008 April 6, Beverly Gage, “Our First Black President?”, in New York Times, retrieved 2017-01-08",
          "text": "[T]he notorious historian William Estabrook Chancellor […] helped assemble a controversial biographical portrait accusing President Warren Harding of covering up his family’s “colored” past. […] Under the one-drop rule of American race relations, Chancellor claimed, the country had inadvertently elected its “first Negro president.”",
          "type": "quotation"
        }
      ],
      "glosses": [
        "The notion that one drop of black blood (i.e., any African ancestry at all) makes a person black."
      ],
      "id": "en-one-drop_rule-en-noun-h9oLOdSS",
      "links": [
        [
          "black",
          "black"
        ],
        [
          "African",
          "African"
        ],
        [
          "ancestry",
          "ancestry"
        ]
      ],
      "raw_glosses": [
        "(chiefly US) The notion that one drop of black blood (i.e., any African ancestry at all) makes a person black."
      ],
      "related": [
        {
          "word": "miscegenation"
        }
      ],
      "tags": [
        "US"
      ],
      "wikipedia": [
        "one-drop rule"
      ]
    }
  ],
  "word": "one-drop rule"
}

{
  "derived": [
    {
      "word": "reverse one-drop rule"
    }
  ],
  "forms": [
    {
      "form": "the one-drop rule",
      "tags": [
        "canonical"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "noun",
        "head": "the one-drop rule"
      },
      "expansion": "the one-drop rule",
      "name": "head"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "miscegenation"
    }
  ],
  "senses": [
    {
      "categories": [
        "American English",
        "English entries with incorrect language header",
        "English entries with topic categories using raw markup",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with non-redundant non-automated sortkeys",
        "English terms with quotations",
        "en:Racism"
      ],
      "examples": [
        {
          "ref": "2008 April 6, Beverly Gage, “Our First Black President?”, in New York Times, retrieved 2017-01-08",
          "text": "[T]he notorious historian William Estabrook Chancellor […] helped assemble a controversial biographical portrait accusing President Warren Harding of covering up his family’s “colored” past. […] Under the one-drop rule of American race relations, Chancellor claimed, the country had inadvertently elected its “first Negro president.”",
          "type": "quotation"
        }
      ],
      "glosses": [
        "The notion that one drop of black blood (i.e., any African ancestry at all) makes a person black."
      ],
      "links": [
        [
          "black",
          "black"
        ],
        [
          "African",
          "African"
        ],
        [
          "ancestry",
          "ancestry"
        ]
      ],
      "raw_glosses": [
        "(chiefly US) The notion that one drop of black blood (i.e., any African ancestry at all) makes a person black."
      ],
      "tags": [
        "US"
      ],
      "wikipedia": [
        "one-drop rule"
      ]
    }
  ],
  "word": "one-drop rule"
}