"O2" meaning in Translingual

{
  "head_templates": [
    {
      "args": {
        "1": "mul",
        "2": "symbol"
      },
      "expansion": "O2",
      "name": "head"
    }
  ],
  "lang": "Translingual",
  "lang_code": "mul",
  "pos": "symbol",
  "senses": [
    {
      "alt_of": [
        {
          "word": "O₂"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "Translingual entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Translingual entries with topic categories using raw markup",
          "parents": [
            "Entries with topic categories using raw markup",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "mul",
          "name": "Chemical formulae",
          "orig": "mul:Chemical formulae",
          "parents": [
            "Chemistry",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "_dis": "5 6 36 53",
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w+disamb"
        }
      ],
      "glosses": [
        "Alternative form of O₂"
      ],
      "id": "en-O2-mul-symbol-LQb0b~p7",
      "links": [
        [
          "O₂",
          "O₂#Translingual"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative"
      ]
    }
  ],
  "word": "O2"
}

{
  "categories": [
    "English entries with incorrect language header",
    "English lemmas",
    "English proper nouns",
    "English symbols",
    "English terms spelled with numbers",
    "English uncountable nouns"
  ],
  "head_templates": [
    {
      "args": {
        "1": "mul",
        "2": "symbol"
      },
      "expansion": "O2",
      "name": "head"
    }
  ],
  "lang": "Translingual",
  "lang_code": "mul",
  "pos": "symbol",
  "senses": [
    {
      "alt_of": [
        {
          "word": "O₂"
        }
      ],
      "categories": [
        "Translingual entries with incorrect language header",
        "Translingual entries with topic categories using raw markup",
        "Translingual lemmas",
        "Translingual symbols",
        "Translingual terms spelled with numbers",
        "mul:Chemical formulae"
      ],
      "glosses": [
        "Alternative form of O₂"
      ],
      "links": [
        [
          "O₂",
          "O₂#Translingual"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative"
      ]
    }
  ],
  "word": "O2"
}