"zül" meaning in Volapük

{
  "head_templates": [
    {
      "args": {
        "1": "vo",
        "2": "numeral"
      },
      "expansion": "zül",
      "name": "head"
    }
  ],
  "lang": "Volapük",
  "lang_code": "vo",
  "pos": "num",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Pages with 2 entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "topical",
          "name": "Volapük cardinal numbers",
          "parents": [
            "Cardinal numbers",
            "Numbers",
            "All topics",
            "Terms by semantic function",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Volapük entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "derived": [
        {
          "word": "zülüm"
        }
      ],
      "examples": [
        {
          "english": "How old are you? I am nine years old.",
          "ref": "1932, Arie de Jong, Leerboek der Wereldtaal, page 28:",
          "text": "Bäldoti kinik labol-li? Labob bäldoti yelas zül.",
          "type": "quote"
        }
      ],
      "glosses": [
        "nine"
      ],
      "id": "en-zül-vo-num-7c2OcBot",
      "links": [
        [
          "nine",
          "nine"
        ]
      ]
    }
  ],
  "word": "zül"
}

{
  "derived": [
    {
      "word": "zülüm"
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "vo",
        "2": "numeral"
      },
      "expansion": "zül",
      "name": "head"
    }
  ],
  "lang": "Volapük",
  "lang_code": "vo",
  "pos": "num",
  "senses": [
    {
      "categories": [
        "Pages with 2 entries",
        "Pages with entries",
        "Volapük cardinal numbers",
        "Volapük entries with incorrect language header",
        "Volapük lemmas",
        "Volapük numerals",
        "Volapük terms with quotations"
      ],
      "examples": [
        {
          "english": "How old are you? I am nine years old.",
          "ref": "1932, Arie de Jong, Leerboek der Wereldtaal, page 28:",
          "text": "Bäldoti kinik labol-li? Labob bäldoti yelas zül.",
          "type": "quote"
        }
      ],
      "glosses": [
        "nine"
      ],
      "links": [
        [
          "nine",
          "nine"
        ]
      ]
    }
  ],
  "word": "zül"
}