"Braun tube" meaning in English

{
  "etymology_text": "Invented by the German physicist Ferdinand Braun in 1897.",
  "forms": [
    {
      "form": "Braun tubes",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "Braun tube (plural Braun tubes)",
      "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"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English entries with language name categories using raw markup",
          "parents": [
            "Entries with language name categories using raw markup",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English terms with non-redundant non-automated sortkeys",
          "parents": [
            "Terms with non-redundant non-automated sortkeys",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "An early cathode ray tube."
      ],
      "id": "en-Braun_tube-en-noun-0yDMPIx5",
      "links": [
        [
          "cathode ray tube",
          "cathode ray tube"
        ]
      ],
      "raw_glosses": [
        "(historical) An early cathode ray tube."
      ],
      "tags": [
        "historical"
      ]
    }
  ],
  "word": "Braun tube"
}

{
  "etymology_text": "Invented by the German physicist Ferdinand Braun in 1897.",
  "forms": [
    {
      "form": "Braun tubes",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "Braun tube (plural Braun 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 historical senses",
        "English terms with non-redundant non-automated sortkeys"
      ],
      "glosses": [
        "An early cathode ray tube."
      ],
      "links": [
        [
          "cathode ray tube",
          "cathode ray tube"
        ]
      ],
      "raw_glosses": [
        "(historical) An early cathode ray tube."
      ],
      "tags": [
        "historical"
      ]
    }
  ],
  "word": "Braun tube"
}