"border state" meaning in English

{
  "forms": [
    {
      "form": "border states",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "nolinkhead": "1"
      },
      "expansion": "border state (plural border states)",
      "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": "topical",
          "langcode": "en",
          "name": "American Civil War",
          "orig": "en:American Civil War",
          "parents": [
            "Historical events",
            "History of the United States",
            "Slavery",
            "War",
            "History",
            "United States",
            "Society",
            "Work",
            "Conflict",
            "Military",
            "Violence",
            "All topics",
            "North America",
            "Human activity",
            "Human behaviour",
            "Fundamental",
            "America",
            "Human",
            "Earth",
            "Nature"
          ],
          "source": "w"
        },
        {
          "kind": "place",
          "langcode": "en",
          "name": "Regions of the United States",
          "orig": "en:Regions of the United States",
          "parents": [
            "Regions",
            "Places",
            "Political subdivisions",
            "Names",
            "Polities",
            "All topics",
            "Proper nouns",
            "Terms by semantic function",
            "Fundamental",
            "Nouns",
            "Lemmas"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Slavery",
          "orig": "en:Slavery",
          "parents": [
            "Society",
            "Work",
            "All topics",
            "Human activity",
            "Fundamental",
            "Human behaviour",
            "Human"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "In the American Civil War, one of the slave states that did not join the Confederacy."
      ],
      "id": "en-border_state-en-noun-hOd5azm0",
      "links": [
        [
          "American Civil War",
          "American Civil War"
        ],
        [
          "slave state",
          "slave state"
        ]
      ]
    }
  ],
  "word": "border state"
}

{
  "forms": [
    {
      "form": "border states",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "nolinkhead": "1"
      },
      "expansion": "border state (plural border states)",
      "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",
        "en:American Civil War",
        "en:Regions of the United States",
        "en:Slavery"
      ],
      "glosses": [
        "In the American Civil War, one of the slave states that did not join the Confederacy."
      ],
      "links": [
        [
          "American Civil War",
          "American Civil War"
        ],
        [
          "slave state",
          "slave state"
        ]
      ]
    }
  ],
  "word": "border state"
}