"na" meaning in Neapolitan

{
  "etymology_templates": [
    {
      "args": {
        "1": "nap",
        "2": "la",
        "3": "una",
        "4": "ūna"
      },
      "expansion": "Latin ūna",
      "name": "der"
    }
  ],
  "etymology_text": "From Latin ūna.",
  "head_templates": [
    {
      "args": {
        "1": "nap",
        "2": "articles",
        "g": "f-s"
      },
      "expansion": "na f sg",
      "name": "head"
    }
  ],
  "lang": "Neapolitan",
  "lang_code": "nap",
  "pos": "article",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Latin links with redundant target parameters",
          "parents": [
            "Links with redundant target parameters",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Neapolitan articles",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Neapolitan entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 109 entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "a, an"
      ],
      "id": "en-na-nap-article-jF9Wbm2d",
      "links": [
        [
          "a",
          "a"
        ],
        [
          "an",
          "an"
        ]
      ],
      "synonyms": [
        {
          "english": "before words starting with a vowel",
          "word": "n'"
        }
      ],
      "tags": [
        "feminine",
        "singular"
      ]
    }
  ],
  "word": "na"
}

{
  "categories": [
    "Pages with 109 entries",
    "Pages with entries"
  ],
  "etymology_templates": [
    {
      "args": {
        "1": "nap",
        "2": "la",
        "3": "una",
        "4": "ūna"
      },
      "expansion": "Latin ūna",
      "name": "der"
    }
  ],
  "etymology_text": "From Latin ūna.",
  "head_templates": [
    {
      "args": {
        "1": "nap",
        "2": "articles",
        "g": "f-s"
      },
      "expansion": "na f sg",
      "name": "head"
    }
  ],
  "lang": "Neapolitan",
  "lang_code": "nap",
  "pos": "article",
  "senses": [
    {
      "categories": [
        "Latin links with redundant target parameters",
        "Neapolitan articles",
        "Neapolitan entries with incorrect language header",
        "Neapolitan lemmas",
        "Neapolitan terms derived from Latin",
        "Pages with 109 entries",
        "Pages with entries"
      ],
      "glosses": [
        "a, an"
      ],
      "links": [
        [
          "a",
          "a"
        ],
        [
          "an",
          "an"
        ]
      ],
      "tags": [
        "feminine",
        "singular"
      ]
    }
  ],
  "synonyms": [
    {
      "english": "before words starting with a vowel",
      "word": "n'"
    }
  ],
  "word": "na"
}