"casco antiguo" meaning in Spanish

{
  "forms": [
    {
      "form": "cascos antiguos",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m"
      },
      "expansion": "casco antiguo m (plural cascos antiguos)",
      "name": "es-noun"
    }
  ],
  "lang": "Spanish",
  "lang_code": "es",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Spanish entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "old town"
      ],
      "id": "en-casco_antiguo-es-noun-s4hKwTwN",
      "links": [
        [
          "old town",
          "old town"
        ]
      ],
      "tags": [
        "masculine"
      ]
    }
  ],
  "word": "casco antiguo"
}

{
  "forms": [
    {
      "form": "cascos antiguos",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m"
      },
      "expansion": "casco antiguo m (plural cascos antiguos)",
      "name": "es-noun"
    }
  ],
  "lang": "Spanish",
  "lang_code": "es",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "Spanish countable nouns",
        "Spanish entries with incorrect language header",
        "Spanish lemmas",
        "Spanish masculine nouns",
        "Spanish multiword terms",
        "Spanish nouns"
      ],
      "glosses": [
        "old town"
      ],
      "links": [
        [
          "old town",
          "old town"
        ]
      ],
      "tags": [
        "masculine"
      ]
    }
  ],
  "word": "casco antiguo"
}