"NAN" meaning in Translingual

{
  "head_templates": [
    {
      "args": {
        "1": "mul",
        "10": "",
        "2": "symbol",
        "3": "",
        "4": "",
        "5": "or",
        "6": "",
        "7": "or",
        "8": "",
        "9": "or",
        "cat2": "",
        "f1lang": "en",
        "f1nolink": "",
        "f2lang": "en",
        "f2nolink": "",
        "f3lang": "en",
        "f3nolink": "",
        "f4lang": "en",
        "f4nolink": "",
        "head": "",
        "head2": "",
        "head3": "",
        "head4": "",
        "sc": "Latn",
        "sort": ""
      },
      "expansion": "NAN",
      "name": "head"
    },
    {
      "args": {},
      "expansion": "NAN",
      "name": "mul-symbol"
    }
  ],
  "lang": "Translingual",
  "lang_code": "mul",
  "pos": "symbol",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "IATA airport codes",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Translingual entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Translingual terms with redundant script codes",
          "parents": [
            "Terms with redundant script codes",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "mul",
          "name": "Aviation",
          "orig": "mul:Aviation",
          "parents": [
            "Aeronautics",
            "Transport",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "_dis": "26 17 26 30",
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w+disamb"
        }
      ],
      "glosses": [
        "IATA airport code for Nadi International Airport, which serves Nadi, Fiji."
      ],
      "id": "en-NAN-mul-symbol-lJy7Njsm",
      "links": [
        [
          "aviation",
          "aviation"
        ],
        [
          "IATA",
          "IATA"
        ],
        [
          "airport",
          "airport"
        ]
      ],
      "qualifier": "international standards",
      "raw_glosses": [
        "(international standards, aviation) IATA airport code for Nadi International Airport, which serves Nadi, Fiji."
      ],
      "topics": [
        "aeronautics",
        "aerospace",
        "aviation",
        "business",
        "engineering",
        "natural-sciences",
        "physical-sciences"
      ]
    }
  ],
  "word": "NAN"
}

{
  "categories": [
    "English countable nouns",
    "English entries with incorrect language header",
    "English lemmas",
    "English nouns",
    "English nouns with unknown or uncertain plurals",
    "English palindromes",
    "English proper nouns",
    "English uncountable nouns"
  ],
  "head_templates": [
    {
      "args": {
        "1": "mul",
        "10": "",
        "2": "symbol",
        "3": "",
        "4": "",
        "5": "or",
        "6": "",
        "7": "or",
        "8": "",
        "9": "or",
        "cat2": "",
        "f1lang": "en",
        "f1nolink": "",
        "f2lang": "en",
        "f2nolink": "",
        "f3lang": "en",
        "f3nolink": "",
        "f4lang": "en",
        "f4nolink": "",
        "head": "",
        "head2": "",
        "head3": "",
        "head4": "",
        "sc": "Latn",
        "sort": ""
      },
      "expansion": "NAN",
      "name": "head"
    },
    {
      "args": {},
      "expansion": "NAN",
      "name": "mul-symbol"
    }
  ],
  "lang": "Translingual",
  "lang_code": "mul",
  "pos": "symbol",
  "senses": [
    {
      "categories": [
        "IATA airport codes",
        "Translingual entries with incorrect language header",
        "Translingual lemmas",
        "Translingual palindromes",
        "Translingual symbols",
        "Translingual terms with redundant script codes",
        "mul:Aviation"
      ],
      "glosses": [
        "IATA airport code for Nadi International Airport, which serves Nadi, Fiji."
      ],
      "links": [
        [
          "aviation",
          "aviation"
        ],
        [
          "IATA",
          "IATA"
        ],
        [
          "airport",
          "airport"
        ]
      ],
      "qualifier": "international standards",
      "raw_glosses": [
        "(international standards, aviation) IATA airport code for Nadi International Airport, which serves Nadi, Fiji."
      ],
      "topics": [
        "aeronautics",
        "aerospace",
        "aviation",
        "business",
        "engineering",
        "natural-sciences",
        "physical-sciences"
      ]
    }
  ],
  "word": "NAN"
}