"fr." meaning in Icelandic

{
  "etymology_templates": [
    {
      "args": {
        "1": "is",
        "2": "frú"
      },
      "expansion": "Abbreviation of frú",
      "name": "abbrev"
    }
  ],
  "etymology_text": "Abbreviation of frú and ungfrú.",
  "head_templates": [
    {
      "args": {
        "1": "f.indecl"
      },
      "expansion": "fr. f (indeclinable)",
      "name": "is-noun"
    }
  ],
  "lang": "Icelandic",
  "lang_code": "is",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Icelandic entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 6 entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Mrs., Miss, Ms."
      ],
      "id": "en-fr.-is-noun-hNZaTRS6",
      "links": [
        [
          "Mrs.",
          "Mrs."
        ],
        [
          "Miss",
          "Miss"
        ],
        [
          "Ms.",
          "Ms."
        ]
      ],
      "tags": [
        "feminine",
        "indeclinable"
      ]
    }
  ],
  "word": "fr."
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "is",
        "2": "frú"
      },
      "expansion": "Abbreviation of frú",
      "name": "abbrev"
    }
  ],
  "etymology_text": "Abbreviation of frú and ungfrú.",
  "head_templates": [
    {
      "args": {
        "1": "f.indecl"
      },
      "expansion": "fr. f (indeclinable)",
      "name": "is-noun"
    }
  ],
  "lang": "Icelandic",
  "lang_code": "is",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "Icelandic 2-letter abbreviations",
        "Icelandic abbreviations",
        "Icelandic entries with incorrect language header",
        "Icelandic feminine nouns",
        "Icelandic indeclinable nouns",
        "Icelandic lemmas",
        "Icelandic nouns",
        "Icelandic terms spelled with .",
        "Icelandic terms with redundant head parameter",
        "Pages with 6 entries",
        "Pages with entries"
      ],
      "glosses": [
        "Mrs., Miss, Ms."
      ],
      "links": [
        [
          "Mrs.",
          "Mrs."
        ],
        [
          "Miss",
          "Miss"
        ],
        [
          "Ms.",
          "Ms."
        ]
      ],
      "tags": [
        "feminine",
        "indeclinable"
      ]
    }
  ],
  "word": "fr."
}