"Geissler tube" meaning in English

{
  "etymology_text": "After Heinrich Geissler, who invented it in 1857.",
  "forms": [
    {
      "form": "Geissler tubes",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "Geissler tube (plural Geissler tubes)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
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      ],
      "glosses": [
        "An early gas discharge tube used to demonstrate the principles of electrical glow discharge."
      ],
      "id": "en-Geissler_tube-en-noun-uxsvtUG5",
      "links": [
        [
          "gas",
          "gas"
        ],
        [
          "discharge",
          "discharge"
        ],
        [
          "tube",
          "tube"
        ],
        [
          "demonstrate",
          "demonstrate"
        ],
        [
          "principle",
          "principle"
        ]
      ],
      "wikipedia": [
        "Geissler tube"
      ]
    }
  ],
  "word": "Geissler tube"
}

{
  "etymology_text": "After Heinrich Geissler, who invented it in 1857.",
  "forms": [
    {
      "form": "Geissler tubes",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "Geissler tube (plural Geissler tubes)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English entries with language name categories using raw markup",
        "English eponyms",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with non-redundant non-automated sortkeys"
      ],
      "glosses": [
        "An early gas discharge tube used to demonstrate the principles of electrical glow discharge."
      ],
      "links": [
        [
          "gas",
          "gas"
        ],
        [
          "discharge",
          "discharge"
        ],
        [
          "tube",
          "tube"
        ],
        [
          "demonstrate",
          "demonstrate"
        ],
        [
          "principle",
          "principle"
        ]
      ],
      "wikipedia": [
        "Geissler tube"
      ]
    }
  ],
  "word": "Geissler tube"
}