"ghost population" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "ghost",
        "3": "population"
      },
      "expansion": "ghost + population",
      "name": "af"
    }
  ],
  "etymology_text": "From ghost + population.",
  "forms": [
    {
      "form": "ghost populations",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "ghost population (plural ghost populations)",
      "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"
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          "source": "w"
        },
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          "kind": "other",
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          "parents": [],
          "source": "w"
        },
        {
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          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "text": "The Ancient North-Eurasians are a ghost population whose existence can be inferred from analysis of European and Native American genes.",
          "type": "example"
        }
      ],
      "glosses": [
        "A population that is inferred to have existed based on data that has been reconstructed rather than on direct sampling."
      ],
      "id": "en-ghost_population-en-noun-B-B6DQSn",
      "links": [
        [
          "population",
          "population"
        ],
        [
          "infer",
          "infer"
        ]
      ],
      "wikipedia": [
        "ghost population"
      ]
    }
  ],
  "word": "ghost population"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "ghost",
        "3": "population"
      },
      "expansion": "ghost + population",
      "name": "af"
    }
  ],
  "etymology_text": "From ghost + population.",
  "forms": [
    {
      "form": "ghost populations",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "ghost population (plural ghost populations)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
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        "English compound terms",
        "English countable nouns",
        "English entries with incorrect language header",
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        "English multiword terms",
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        "English terms with usage examples",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "examples": [
        {
          "text": "The Ancient North-Eurasians are a ghost population whose existence can be inferred from analysis of European and Native American genes.",
          "type": "example"
        }
      ],
      "glosses": [
        "A population that is inferred to have existed based on data that has been reconstructed rather than on direct sampling."
      ],
      "links": [
        [
          "population",
          "population"
        ],
        [
          "infer",
          "infer"
        ]
      ],
      "wikipedia": [
        "ghost population"
      ]
    }
  ],
  "word": "ghost population"
}