"battleground state" meaning in English

{
  "forms": [
    {
      "form": "battleground states",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "battleground state (plural battleground 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": "US politics",
          "orig": "en:US politics",
          "parents": [
            "Politics",
            "United States",
            "Society",
            "North America",
            "All topics",
            "America",
            "Fundamental",
            "Earth",
            "Nature"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A state which is roughly as likely to vote Republican as Democrat in a given election."
      ],
      "id": "en-battleground_state-en-noun-DeAy6VwE",
      "links": [
        [
          "Republican",
          "Republican"
        ],
        [
          "Democrat",
          "Democrat"
        ],
        [
          "election",
          "election"
        ]
      ],
      "raw_glosses": [
        "(US politics) A state which is roughly as likely to vote Republican as Democrat in a given election."
      ],
      "related": [
        {
          "word": "blue state"
        },
        {
          "word": "green state"
        },
        {
          "word": "red state"
        }
      ],
      "synonyms": [
        {
          "word": "swing state"
        },
        {
          "word": "purple state"
        }
      ],
      "tags": [
        "US"
      ],
      "topics": [
        "government",
        "politics"
      ]
    }
  ],
  "word": "battleground state"
}

{
  "forms": [
    {
      "form": "battleground states",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "battleground state (plural battleground states)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "blue state"
    },
    {
      "word": "green state"
    },
    {
      "word": "red state"
    }
  ],
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "en:US politics"
      ],
      "glosses": [
        "A state which is roughly as likely to vote Republican as Democrat in a given election."
      ],
      "links": [
        [
          "Republican",
          "Republican"
        ],
        [
          "Democrat",
          "Democrat"
        ],
        [
          "election",
          "election"
        ]
      ],
      "raw_glosses": [
        "(US politics) A state which is roughly as likely to vote Republican as Democrat in a given election."
      ],
      "synonyms": [
        {
          "word": "swing state"
        },
        {
          "word": "purple state"
        }
      ],
      "tags": [
        "US"
      ],
      "topics": [
        "government",
        "politics"
      ]
    }
  ],
  "word": "battleground state"
}