"Fe" meaning in Translingual

{
  "etymology_templates": [
    {
      "args": {
        "1": "mul",
        "2": "la",
        "3": "ferrum",
        "4": "",
        "5": "iron"
      },
      "expansion": "Latin ferrum (“iron”)",
      "name": "der"
    }
  ],
  "etymology_text": "From Latin ferrum (“iron”).",
  "head_templates": [
    {
      "args": {
        "1": "mul",
        "2": "symbol"
      },
      "expansion": "Fe",
      "name": "head"
    }
  ],
  "lang": "Translingual",
  "lang_code": "mul",
  "pos": "symbol",
  "senses": [
    {
      "categories": [
        {
          "kind": "topical",
          "name": "Symbols for chemical elements",
          "parents": [
            "Chemical elements",
            "Matter",
            "Chemistry",
            "Nature",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Translingual entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "derived": [
        {
          "word": "nife"
        }
      ],
      "glosses": [
        "iron."
      ],
      "id": "en-Fe-mul-symbol-HKWMNyFW",
      "links": [
        [
          "chemistry",
          "chemistry"
        ],
        [
          "iron",
          "iron"
        ]
      ],
      "raw_glosses": [
        "(chemistry) iron."
      ],
      "topics": [
        "chemistry",
        "natural-sciences",
        "physical-sciences"
      ]
    }
  ],
  "word": "Fe"
}

{
  "derived": [
    {
      "word": "nife"
    }
  ],
  "etymology_templates": [
    {
      "args": {
        "1": "mul",
        "2": "la",
        "3": "ferrum",
        "4": "",
        "5": "iron"
      },
      "expansion": "Latin ferrum (“iron”)",
      "name": "der"
    }
  ],
  "etymology_text": "From Latin ferrum (“iron”).",
  "head_templates": [
    {
      "args": {
        "1": "mul",
        "2": "symbol"
      },
      "expansion": "Fe",
      "name": "head"
    }
  ],
  "lang": "Translingual",
  "lang_code": "mul",
  "pos": "symbol",
  "senses": [
    {
      "categories": [
        "Symbols for chemical elements",
        "Translingual entries with incorrect language header",
        "Translingual lemmas",
        "Translingual symbols",
        "Translingual terms derived from Latin"
      ],
      "glosses": [
        "iron."
      ],
      "links": [
        [
          "chemistry",
          "chemistry"
        ],
        [
          "iron",
          "iron"
        ]
      ],
      "raw_glosses": [
        "(chemistry) iron."
      ],
      "topics": [
        "chemistry",
        "natural-sciences",
        "physical-sciences"
      ]
    }
  ],
  "word": "Fe"
}