"ultrafine particle" meaning in English

{
  "forms": [
    {
      "form": "ultrafine particles",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "ultrafine particle (plural ultrafine particles)",
      "name": "en-noun"
    }
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  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
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          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
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          "source": "w"
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      ],
      "glosses": [
        "A particle with diameter less than about 100 nanometers (nm)."
      ],
      "id": "en-ultrafine_particle-en-noun-3CiZvnvb",
      "links": [
        [
          "nanometer",
          "nanometer"
        ]
      ],
      "related": [
        {
          "word": "nanotechnology"
        },
        {
          "word": "quantum dot"
        },
        {
          "word": "nanoparticle"
        }
      ],
      "synonyms": [
        {
          "word": "nanoparticle"
        }
      ]
    }
  ],
  "word": "ultrafine particle"
}

{
  "forms": [
    {
      "form": "ultrafine particles",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "ultrafine particle (plural ultrafine particles)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "nanotechnology"
    },
    {
      "word": "quantum dot"
    },
    {
      "word": "nanoparticle"
    }
  ],
  "senses": [
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        "English multiword terms",
        "English nouns",
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      ],
      "glosses": [
        "A particle with diameter less than about 100 nanometers (nm)."
      ],
      "links": [
        [
          "nanometer",
          "nanometer"
        ]
      ]
    }
  ],
  "synonyms": [
    {
      "word": "nanoparticle"
    }
  ],
  "word": "ultrafine particle"
}