"Crookes space" meaning in English

{
  "etymology_text": "After Sir William Crookes, English chemist, who first described it.",
  "forms": [
    {
      "form": "Crookes spaces",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "Crookes space (plural Crookes spaces)",
      "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"
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          "source": "w"
        },
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        },
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          "kind": "topical",
          "langcode": "en",
          "name": "Physics",
          "orig": "en:Physics",
          "parents": [
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "The dark space within the negative-pole glow at the cathode of a vacuum tube, observed only when the pressure is low enough to give a striated discharge."
      ],
      "id": "en-Crookes_space-en-noun-JLMX0sCd",
      "links": [
        [
          "physics",
          "physics"
        ],
        [
          "negative",
          "negative"
        ],
        [
          "pole",
          "pole"
        ],
        [
          "glow",
          "glow"
        ],
        [
          "cathode",
          "cathode"
        ],
        [
          "vacuum tube",
          "vacuum tube"
        ],
        [
          "pressure",
          "pressure"
        ],
        [
          "striated",
          "striated"
        ],
        [
          "discharge",
          "discharge"
        ]
      ],
      "raw_glosses": [
        "(physics, dated) The dark space within the negative-pole glow at the cathode of a vacuum tube, observed only when the pressure is low enough to give a striated discharge."
      ],
      "synonyms": [
        {
          "word": "Crookes layer"
        }
      ],
      "tags": [
        "dated"
      ],
      "topics": [
        "natural-sciences",
        "physical-sciences",
        "physics"
      ]
    }
  ],
  "word": "Crookes space"
}

{
  "etymology_text": "After Sir William Crookes, English chemist, who first described it.",
  "forms": [
    {
      "form": "Crookes spaces",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "Crookes space (plural Crookes spaces)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
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        "English countable nouns",
        "English dated terms",
        "English entries with incorrect language header",
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        "English multiword terms",
        "English nouns",
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        "en:Physics"
      ],
      "glosses": [
        "The dark space within the negative-pole glow at the cathode of a vacuum tube, observed only when the pressure is low enough to give a striated discharge."
      ],
      "links": [
        [
          "physics",
          "physics"
        ],
        [
          "negative",
          "negative"
        ],
        [
          "pole",
          "pole"
        ],
        [
          "glow",
          "glow"
        ],
        [
          "cathode",
          "cathode"
        ],
        [
          "vacuum tube",
          "vacuum tube"
        ],
        [
          "pressure",
          "pressure"
        ],
        [
          "striated",
          "striated"
        ],
        [
          "discharge",
          "discharge"
        ]
      ],
      "raw_glosses": [
        "(physics, dated) The dark space within the negative-pole glow at the cathode of a vacuum tube, observed only when the pressure is low enough to give a striated discharge."
      ],
      "tags": [
        "dated"
      ],
      "topics": [
        "natural-sciences",
        "physical-sciences",
        "physics"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "Crookes layer"
    }
  ],
  "word": "Crookes space"
}