"ad un tratto" meaning in Italian

{
  "head_templates": [
    {
      "args": {},
      "expansion": "ad un tratto",
      "name": "it-adv"
    }
  ],
  "lang": "Italian",
  "lang_code": "it",
  "pos": "adv",
  "senses": [
    {
      "alt_of": [
        {
          "word": "d'un tratto"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "Italian entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "english": "(please add an English translation of this quotation)",
          "ref": "1970, “L'appuntamento”, Bruno Lauzi (lyrics), R. Carlos and E. Carlos (music), performed by Ornella Vanoni",
          "text": "Sto aspettando quando ad un tratto ti vedrò spuntare in lontananza!",
          "type": "quotation"
        }
      ],
      "glosses": [
        "Alternative form of d'un tratto"
      ],
      "id": "en-ad_un_tratto-it-adv-Lu57t8I6",
      "links": [
        [
          "d'un tratto",
          "d'un tratto#Italian"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative"
      ]
    }
  ],
  "word": "ad un tratto"
}

{
  "head_templates": [
    {
      "args": {},
      "expansion": "ad un tratto",
      "name": "it-adv"
    }
  ],
  "lang": "Italian",
  "lang_code": "it",
  "pos": "adv",
  "senses": [
    {
      "alt_of": [
        {
          "word": "d'un tratto"
        }
      ],
      "categories": [
        "Italian adverbs",
        "Italian entries with incorrect language header",
        "Italian lemmas",
        "Italian multiword terms",
        "Italian terms with quotations",
        "Requests for translations of Italian quotations"
      ],
      "examples": [
        {
          "english": "(please add an English translation of this quotation)",
          "ref": "1970, “L'appuntamento”, Bruno Lauzi (lyrics), R. Carlos and E. Carlos (music), performed by Ornella Vanoni",
          "text": "Sto aspettando quando ad un tratto ti vedrò spuntare in lontananza!",
          "type": "quotation"
        }
      ],
      "glosses": [
        "Alternative form of d'un tratto"
      ],
      "links": [
        [
          "d'un tratto",
          "d'un tratto#Italian"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative"
      ]
    }
  ],
  "word": "ad un tratto"
}