"DX" meaning in Translingual

{
  "head_templates": [
    {
      "args": {
        "1": "mul",
        "2": "symbol"
      },
      "expansion": "DX",
      "name": "head"
    }
  ],
  "lang": "Translingual",
  "lang_code": "mul",
  "pos": "symbol",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Translingual entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "(long) distance"
      ],
      "id": "en-DX-mul-symbol-ISkdLan4",
      "links": [
        [
          "radio",
          "radio"
        ],
        [
          "slang",
          "slang"
        ],
        [
          "distance",
          "distance"
        ]
      ],
      "raw_glosses": [
        "(radio slang) (long) distance"
      ],
      "tags": [
        "slang"
      ],
      "topics": [
        "broadcasting",
        "media",
        "radio"
      ]
    }
  ],
  "word": "DX"
}

{
  "categories": [
    "English adjectives",
    "English countable nouns",
    "English entries with incorrect language header",
    "English lemmas",
    "English nouns",
    "English nouns with unknown or uncertain plurals",
    "English uncomparable adjectives",
    "English verbs",
    "English words without vowels"
  ],
  "head_templates": [
    {
      "args": {
        "1": "mul",
        "2": "symbol"
      },
      "expansion": "DX",
      "name": "head"
    }
  ],
  "lang": "Translingual",
  "lang_code": "mul",
  "pos": "symbol",
  "senses": [
    {
      "categories": [
        "Translingual entries with incorrect language header",
        "Translingual lemmas",
        "Translingual radio slang",
        "Translingual symbols"
      ],
      "glosses": [
        "(long) distance"
      ],
      "links": [
        [
          "radio",
          "radio"
        ],
        [
          "slang",
          "slang"
        ],
        [
          "distance",
          "distance"
        ]
      ],
      "raw_glosses": [
        "(radio slang) (long) distance"
      ],
      "tags": [
        "slang"
      ],
      "topics": [
        "broadcasting",
        "media",
        "radio"
      ]
    }
  ],
  "word": "DX"
}