"pumice raft" meaning in English

{
  "forms": [
    {
      "form": "pumice rafts",
      "tags": [
        "plural"
      ]
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  "head_templates": [
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      "args": {},
      "expansion": "pumice raft (plural pumice rafts)",
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  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
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      "glosses": [
        "A collection of pumice stones that form a floating island of rock and sand, as pumice is less dense than water."
      ],
      "id": "en-pumice_raft-en-noun-S0upaww2",
      "translations": [
        {
          "code": "fi",
          "lang": "Finnish",
          "sense": "floating island of pumice rock",
          "word": "hohkakivilautta"
        }
      ]
    }
  ],
  "word": "pumice raft"
}

{
  "forms": [
    {
      "form": "pumice rafts",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "pumice raft (plural pumice rafts)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
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        "English countable nouns",
        "English entries with incorrect language header",
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        "English multiword terms",
        "English nouns",
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      "glosses": [
        "A collection of pumice stones that form a floating island of rock and sand, as pumice is less dense than water."
      ]
    }
  ],
  "translations": [
    {
      "code": "fi",
      "lang": "Finnish",
      "sense": "floating island of pumice rock",
      "word": "hohkakivilautta"
    }
  ],
  "word": "pumice raft"
}