"pivot bridge" meaning in English

{
  "forms": [
    {
      "form": "pivot bridges",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "pivot bridge (plural pivot bridges)",
      "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": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Bridges",
          "orig": "en:Bridges",
          "parents": [
            "Buildings and structures",
            "Architecture",
            "Applied sciences",
            "Art",
            "Sciences",
            "Culture",
            "All topics",
            "Society",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A form of drawbridge in which one span, called the pivot span, turns about a central vertical axis."
      ],
      "id": "en-pivot_bridge-en-noun--omFlKZ6",
      "links": [
        [
          "drawbridge",
          "drawbridge"
        ],
        [
          "span",
          "span"
        ],
        [
          "vertical",
          "vertical"
        ],
        [
          "axis",
          "axis"
        ]
      ]
    }
  ],
  "word": "pivot bridge"
}

{
  "forms": [
    {
      "form": "pivot bridges",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "pivot bridge (plural pivot bridges)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Bridges"
      ],
      "glosses": [
        "A form of drawbridge in which one span, called the pivot span, turns about a central vertical axis."
      ],
      "links": [
        [
          "drawbridge",
          "drawbridge"
        ],
        [
          "span",
          "span"
        ],
        [
          "vertical",
          "vertical"
        ],
        [
          "axis",
          "axis"
        ]
      ]
    }
  ],
  "word": "pivot bridge"
}