"drop bolt" meaning in English

{
  "forms": [
    {
      "form": "drop bolts",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "drop bolt (plural drop bolts)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [],
      "examples": [
        {
          "bold_text_offsets": [
            [
              57,
              67
            ]
          ],
          "ref": "1888, Rudyard Kipling, “The Phantom Rickshaw”, in The Phantom 'Rickshaw and Other Tales, Allahabad: A.H. Wheeler and Co., page 9:",
          "text": "Speaking now as a condemned criminal might speak ere the drop-bolts are drawn, my story, wild and hideously improbable as it may appear, demands at least attention.",
          "type": "quote"
        }
      ],
      "glosses": [
        "A bolt that holds a trapdoor shut."
      ],
      "id": "en-drop_bolt-en-noun-YznusnQd"
    },
    {
      "categories": [
        {
          "_dis": "20 80",
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [],
          "source": "w+disamb"
        },
        {
          "_dis": "6 94",
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w+disamb"
        },
        {
          "_dis": "6 94",
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w+disamb"
        }
      ],
      "glosses": [
        "A bolt that drops into place when let go."
      ],
      "id": "en-drop_bolt-en-noun-GUESsjgd"
    }
  ],
  "word": "drop bolt"
}

{
  "categories": [
    "English countable nouns",
    "English entries with incorrect language header",
    "English lemmas",
    "English multiword terms",
    "English nouns",
    "Pages with 1 entry",
    "Pages with entries"
  ],
  "forms": [
    {
      "form": "drop bolts",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "drop bolt (plural drop bolts)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English terms with quotations"
      ],
      "examples": [
        {
          "bold_text_offsets": [
            [
              57,
              67
            ]
          ],
          "ref": "1888, Rudyard Kipling, “The Phantom Rickshaw”, in The Phantom 'Rickshaw and Other Tales, Allahabad: A.H. Wheeler and Co., page 9:",
          "text": "Speaking now as a condemned criminal might speak ere the drop-bolts are drawn, my story, wild and hideously improbable as it may appear, demands at least attention.",
          "type": "quote"
        }
      ],
      "glosses": [
        "A bolt that holds a trapdoor shut."
      ]
    },
    {
      "glosses": [
        "A bolt that drops into place when let go."
      ]
    }
  ],
  "word": "drop bolt"
}