"dek du" meaning in Esperanto

{
  "head_templates": [
    {
      "args": {
        "1": "eo",
        "2": "numeral"
      },
      "expansion": "dek du",
      "name": "head"
    }
  ],
  "hyphenation": [
    "dek"
  ],
  "lang": "Esperanto",
  "lang_code": "eo",
  "pos": "num",
  "senses": [
    {
      "categories": [
        {
          "kind": "topical",
          "name": "Esperanto cardinal numbers",
          "parents": [
            "Cardinal numbers",
            "Numbers",
            "All topics",
            "Terms by semantic function",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Esperanto entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "derived": [
        {
          "english": "twelve-year-old",
          "tags": [
            "adjective"
          ],
          "word": "dekdujara"
        }
      ],
      "examples": [
        {
          "english": "For my four children I bought twelve apples",
          "ref": "1903, L. L. Zamenhof, Fundamenta Krestomatio",
          "text": "Por miaj kvar infanoj mi aĉetis dek du pomojn",
          "type": "quotation"
        }
      ],
      "glosses": [
        "twelve"
      ],
      "id": "en-dek_du-eo-num-0adJrYeb",
      "links": [
        [
          "twelve",
          "twelve"
        ]
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "[dek du]"
    }
  ],
  "word": "dek du"
}

{
  "derived": [
    {
      "english": "twelve-year-old",
      "tags": [
        "adjective"
      ],
      "word": "dekdujara"
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "eo",
        "2": "numeral"
      },
      "expansion": "dek du",
      "name": "head"
    }
  ],
  "hyphenation": [
    "dek"
  ],
  "lang": "Esperanto",
  "lang_code": "eo",
  "pos": "num",
  "senses": [
    {
      "categories": [
        "Esperanto cardinal numbers",
        "Esperanto entries with incorrect language header",
        "Esperanto lemmas",
        "Esperanto multiword terms",
        "Esperanto numerals",
        "Esperanto terms with IPA pronunciation",
        "Esperanto terms with audio links",
        "Esperanto terms with quotations",
        "Quotation templates to be cleaned"
      ],
      "examples": [
        {
          "english": "For my four children I bought twelve apples",
          "ref": "1903, L. L. Zamenhof, Fundamenta Krestomatio",
          "text": "Por miaj kvar infanoj mi aĉetis dek du pomojn",
          "type": "quotation"
        }
      ],
      "glosses": [
        "twelve"
      ],
      "links": [
        [
          "twelve",
          "twelve"
        ]
      ]
    }
  ],
  "sounds": [
    {
      "ipa": "[dek du]"
    }
  ],
  "word": "dek du"
}