"indefinite call sign" meaning in English

{
  "forms": [
    {
      "form": "indefinite call signs",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "head": "indefinite call sign"
      },
      "expansion": "indefinite call sign (plural indefinite call signs)",
      "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": "Military",
          "orig": "en:Military",
          "parents": [
            "Society",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A call sign which does not represent a specific facility, command, authority, activity, or unit, but which may represent any one or any group of these."
      ],
      "id": "en-indefinite_call_sign-en-noun-UUWyvEEq",
      "links": [
        [
          "military",
          "military"
        ]
      ],
      "raw_glosses": [
        "(military) A call sign which does not represent a specific facility, command, authority, activity, or unit, but which may represent any one or any group of these."
      ],
      "related": [
        {
          "word": "call sign"
        }
      ],
      "topics": [
        "government",
        "military",
        "politics",
        "war"
      ]
    }
  ],
  "word": "indefinite call sign"
}

{
  "forms": [
    {
      "form": "indefinite call signs",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "head": "indefinite call sign"
      },
      "expansion": "indefinite call sign (plural indefinite call signs)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "call sign"
    }
  ],
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "en:Military"
      ],
      "glosses": [
        "A call sign which does not represent a specific facility, command, authority, activity, or unit, but which may represent any one or any group of these."
      ],
      "links": [
        [
          "military",
          "military"
        ]
      ],
      "raw_glosses": [
        "(military) A call sign which does not represent a specific facility, command, authority, activity, or unit, but which may represent any one or any group of these."
      ],
      "topics": [
        "government",
        "military",
        "politics",
        "war"
      ]
    }
  ],
  "word": "indefinite call sign"
}