"pincer gate" meaning in English

{
  "forms": [
    {
      "form": "pincer gates",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "pincer gate (plural pincer gates)",
      "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",
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          "source": "w"
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      ],
      "glosses": [
        "A gate in a fortification that is deeply embedded between two inward-angled exterior walls, so that those wishing to enter must approach along what is in effect a sunken road and can be easily attacked if necessary."
      ],
      "id": "en-pincer_gate-en-noun-7zKkYKts",
      "links": [
        [
          "gate",
          "gate"
        ],
        [
          "fortification",
          "fortification"
        ]
      ]
    }
  ],
  "word": "pincer gate"
}

{
  "forms": [
    {
      "form": "pincer gates",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "pincer gate (plural pincer gates)",
      "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"
      ],
      "glosses": [
        "A gate in a fortification that is deeply embedded between two inward-angled exterior walls, so that those wishing to enter must approach along what is in effect a sunken road and can be easily attacked if necessary."
      ],
      "links": [
        [
          "gate",
          "gate"
        ],
        [
          "fortification",
          "fortification"
        ]
      ]
    }
  ],
  "word": "pincer gate"
}