"a km zero" meaning in Italian

{
  "head_templates": [
    {
      "args": {
        "1": "prepositional phrase"
      },
      "expansion": "a km zero",
      "name": "it-pos"
    }
  ],
  "lang": "Italian",
  "lang_code": "it",
  "pos": "prep_phrase",
  "senses": [
    {
      "alt_of": [
        {
          "word": "a chilometro zero"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "Italian entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Alternative spelling of a chilometro zero"
      ],
      "id": "en-a_km_zero-it-prep_phrase-cr23Z9nZ",
      "links": [
        [
          "a chilometro zero",
          "a chilometro zero#Italian"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative"
      ]
    }
  ],
  "word": "a km zero"
}

{
  "head_templates": [
    {
      "args": {
        "1": "prepositional phrase"
      },
      "expansion": "a km zero",
      "name": "it-pos"
    }
  ],
  "lang": "Italian",
  "lang_code": "it",
  "pos": "prep_phrase",
  "senses": [
    {
      "alt_of": [
        {
          "word": "a chilometro zero"
        }
      ],
      "categories": [
        "Italian entries with incorrect language header",
        "Italian lemmas",
        "Italian multiword terms",
        "Italian prepositional phrases",
        "Italian terms spelled with K",
        "Pages with 1 entry"
      ],
      "glosses": [
        "Alternative spelling of a chilometro zero"
      ],
      "links": [
        [
          "a chilometro zero",
          "a chilometro zero#Italian"
        ]
      ],
      "tags": [
        "alt-of",
        "alternative"
      ]
    }
  ],
  "word": "a km zero"
}