"Planck density" meaning in English

{
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      "form": "Planck densities",
      "tags": [
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      "expansion": "Planck density (plural Planck densities)",
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  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
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          "name": "English entries with incorrect language header",
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          "orig": "en:Physics",
          "parents": [
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      ],
      "glosses": [
        "The unit of density in the system of Planck units, equal to one Planck mass in one Planck volume."
      ],
      "id": "en-Planck_density-en-noun-Vj5B0CPY",
      "links": [
        [
          "physics",
          "physics"
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        [
          "density",
          "density"
        ],
        [
          "Planck unit",
          "Planck unit"
        ],
        [
          "Planck mass",
          "Planck mass"
        ],
        [
          "Planck volume",
          "Planck volume"
        ]
      ],
      "raw_glosses": [
        "(physics) The unit of density in the system of Planck units, equal to one Planck mass in one Planck volume."
      ],
      "topics": [
        "natural-sciences",
        "physical-sciences",
        "physics"
      ]
    }
  ],
  "word": "Planck density"
}

{
  "forms": [
    {
      "form": "Planck densities",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
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      "expansion": "Planck density (plural Planck densities)",
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  "lang_code": "en",
  "pos": "noun",
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        "English entries with incorrect language header",
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      "glosses": [
        "The unit of density in the system of Planck units, equal to one Planck mass in one Planck volume."
      ],
      "links": [
        [
          "physics",
          "physics"
        ],
        [
          "density",
          "density"
        ],
        [
          "Planck unit",
          "Planck unit"
        ],
        [
          "Planck mass",
          "Planck mass"
        ],
        [
          "Planck volume",
          "Planck volume"
        ]
      ],
      "raw_glosses": [
        "(physics) The unit of density in the system of Planck units, equal to one Planck mass in one Planck volume."
      ],
      "topics": [
        "natural-sciences",
        "physical-sciences",
        "physics"
      ]
    }
  ],
  "word": "Planck density"
}