"shield wall" meaning in English

{
  "forms": [
    {
      "form": "shield walls",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "shield wall (plural shield walls)",
      "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": "Entries with translation boxes",
          "parents": [],
          "source": "w"
        },
        {
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          "kind": "other",
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        },
        {
          "kind": "other",
          "name": "Terms with Old Norse translations",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "A \"wall\" of overlapping shields formed by medieval soldiers standing next to each other"
      ],
      "id": "en-shield_wall-en-noun-6GXApZM3",
      "links": [
        [
          "wall",
          "wall"
        ],
        [
          "shield",
          "shield"
        ],
        [
          "soldier",
          "soldier"
        ]
      ],
      "translations": [
        {
          "code": "non",
          "lang": "Old Norse",
          "sense": "wall of overlapping shields",
          "tags": [
            "feminine"
          ],
          "word": "skjaldborg"
        }
      ],
      "wikipedia": [
        "shield wall"
      ]
    }
  ],
  "word": "shield wall"
}

{
  "forms": [
    {
      "form": "shield walls",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "shield wall (plural shield walls)",
      "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",
        "Entries with translation boxes",
        "Pages with 1 entry",
        "Pages with entries",
        "Terms with Old Norse translations"
      ],
      "glosses": [
        "A \"wall\" of overlapping shields formed by medieval soldiers standing next to each other"
      ],
      "links": [
        [
          "wall",
          "wall"
        ],
        [
          "shield",
          "shield"
        ],
        [
          "soldier",
          "soldier"
        ]
      ],
      "wikipedia": [
        "shield wall"
      ]
    }
  ],
  "translations": [
    {
      "code": "non",
      "lang": "Old Norse",
      "sense": "wall of overlapping shields",
      "tags": [
        "feminine"
      ],
      "word": "skjaldborg"
    }
  ],
  "word": "shield wall"
}