"walled plain" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "walled",
        "3": "plain"
      },
      "expansion": "walled + plain",
      "name": "com"
    }
  ],
  "etymology_text": "From walled + plain.",
  "forms": [
    {
      "form": "walled plains",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "walled plain (plural walled plains)",
      "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",
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          "source": "w"
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          "source": "w"
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        {
          "kind": "topical",
          "langcode": "en",
          "name": "Astronomy",
          "orig": "en:Astronomy",
          "parents": [
            "Sciences",
            "Space",
            "All topics",
            "Nature",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A large impact crater that has a relatively flat floor, surrounded by a wall"
      ],
      "id": "en-walled_plain-en-noun-JhV0hfOs",
      "links": [
        [
          "astronomy",
          "astronomy"
        ],
        [
          "impact crater",
          "impact crater"
        ],
        [
          "wall",
          "wall"
        ]
      ],
      "raw_glosses": [
        "(astronomy) A large impact crater that has a relatively flat floor, surrounded by a wall"
      ],
      "topics": [
        "astronomy",
        "natural-sciences"
      ]
    }
  ],
  "sounds": [
    {
      "rhymes": "-eɪn"
    }
  ],
  "word": "walled plain"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "walled",
        "3": "plain"
      },
      "expansion": "walled + plain",
      "name": "com"
    }
  ],
  "etymology_text": "From walled + plain.",
  "forms": [
    {
      "form": "walled plains",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "walled plain (plural walled plains)",
      "name": "en-noun"
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  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
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        "English compound terms",
        "English countable nouns",
        "English entries with incorrect language header",
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        "Rhymes:English/eɪn",
        "Rhymes:English/eɪn/2 syllables",
        "en:Astronomy"
      ],
      "glosses": [
        "A large impact crater that has a relatively flat floor, surrounded by a wall"
      ],
      "links": [
        [
          "astronomy",
          "astronomy"
        ],
        [
          "impact crater",
          "impact crater"
        ],
        [
          "wall",
          "wall"
        ]
      ],
      "raw_glosses": [
        "(astronomy) A large impact crater that has a relatively flat floor, surrounded by a wall"
      ],
      "topics": [
        "astronomy",
        "natural-sciences"
      ]
    }
  ],
  "sounds": [
    {
      "rhymes": "-eɪn"
    }
  ],
  "word": "walled plain"
}