"iron house" meaning in English

{
  "forms": [
    {
      "form": "iron houses",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "iron house (plural iron houses)",
      "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"
        }
      ],
      "examples": [
        {
          "ref": "1983 December 10, anonymous author, “We Screw Ourselves”, in Gay Community News, volume 11, number 21, page 4:",
          "text": "I do realize that the institution where I am is one of the most lenient in the country and we are not harassed much, security is not tight, and there is no danger from either staff or other inmates so there are not reasons for bitching here as there are for so many of our Brothers and Sisters in other iron houses across this nation.",
          "type": "quote"
        }
      ],
      "glosses": [
        "prison"
      ],
      "id": "en-iron_house-en-noun-TVkbdrcX",
      "links": [
        [
          "prison",
          "prison"
        ]
      ],
      "raw_glosses": [
        "(slang) prison"
      ],
      "tags": [
        "slang"
      ]
    }
  ],
  "word": "iron house"
}

{
  "forms": [
    {
      "form": "iron houses",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "iron house (plural iron houses)",
      "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",
        "English slang",
        "English terms with quotations",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "examples": [
        {
          "ref": "1983 December 10, anonymous author, “We Screw Ourselves”, in Gay Community News, volume 11, number 21, page 4:",
          "text": "I do realize that the institution where I am is one of the most lenient in the country and we are not harassed much, security is not tight, and there is no danger from either staff or other inmates so there are not reasons for bitching here as there are for so many of our Brothers and Sisters in other iron houses across this nation.",
          "type": "quote"
        }
      ],
      "glosses": [
        "prison"
      ],
      "links": [
        [
          "prison",
          "prison"
        ]
      ],
      "raw_glosses": [
        "(slang) prison"
      ],
      "tags": [
        "slang"
      ]
    }
  ],
  "word": "iron house"
}