"BR" meaning in Italian

{
  "head_templates": [
    {
      "args": {
        "1": "f-p"
      },
      "expansion": "BR f pl (plural only)",
      "name": "it-proper noun"
    }
  ],
  "lang": "Italian",
  "lang_code": "it",
  "pos": "name",
  "senses": [
    {
      "alt_of": [
        {
          "extra": "Red Brigades",
          "word": "Brigate Rosse"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "Italian entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Italian links with redundant alt parameters",
          "parents": [
            "Links with redundant alt parameters",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Italian links with redundant wikilinks",
          "parents": [
            "Links with redundant wikilinks",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Italian pluralia tantum",
          "parents": [
            "Pluralia tantum",
            "Nouns",
            "Lemmas"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 5 entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Initialism of Brigate Rosse (Red Brigades)"
      ],
      "id": "en-BR-it-name-Ey7AV91f",
      "links": [
        [
          "Brigate Rosse",
          "w:it:Brigate Rosse"
        ]
      ],
      "tags": [
        "abbreviation",
        "alt-of",
        "feminine",
        "initialism",
        "plural",
        "plural-only"
      ]
    }
  ],
  "word": "BR"
}

{
  "head_templates": [
    {
      "args": {
        "1": "f-p"
      },
      "expansion": "BR f pl (plural only)",
      "name": "it-proper noun"
    }
  ],
  "lang": "Italian",
  "lang_code": "it",
  "pos": "name",
  "senses": [
    {
      "alt_of": [
        {
          "extra": "Red Brigades",
          "word": "Brigate Rosse"
        }
      ],
      "categories": [
        "Italian entries with incorrect language header",
        "Italian feminine nouns",
        "Italian initialisms",
        "Italian lemmas",
        "Italian links with redundant alt parameters",
        "Italian links with redundant wikilinks",
        "Italian pluralia tantum",
        "Italian proper nouns",
        "Pages with 5 entries",
        "Pages with entries"
      ],
      "glosses": [
        "Initialism of Brigate Rosse (Red Brigades)"
      ],
      "links": [
        [
          "Brigate Rosse",
          "w:it:Brigate Rosse"
        ]
      ],
      "tags": [
        "abbreviation",
        "alt-of",
        "feminine",
        "initialism",
        "plural",
        "plural-only"
      ]
    }
  ],
  "word": "BR"
}