"oak apple" meaning in English

{
  "forms": [
    {
      "form": "oak apples",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "oak apple (plural oak apples)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
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          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "lifeform",
          "langcode": "en",
          "name": "Hymenopterans",
          "orig": "en:Hymenopterans",
          "parents": [
            "Insects",
            "Arthropods",
            "Animals",
            "Lifeforms",
            "All topics",
            "Life",
            "Fundamental",
            "Nature"
          ],
          "source": "w"
        },
        {
          "kind": "lifeform",
          "langcode": "en",
          "name": "Oaks",
          "orig": "en:Oaks",
          "parents": [
            "Beech family plants",
            "Trees",
            "Fagales order plants",
            "Plants",
            "Shrubs",
            "Lifeforms",
            "All topics",
            "Life",
            "Fundamental",
            "Nature"
          ],
          "source": "w"
        }
      ],
      "derived": [
        {
          "word": "Oak Apple Day"
        }
      ],
      "examples": [
        {
          "ref": "1665, Robert Hooke, Micrographia, section XXV:",
          "text": "[T]he small Apples which I have often observ'd to grow on the leaves of an Oak call'd Oak-apples […] are nothing but the Matrices of an Insect, as I elsewhere show.",
          "type": "quote"
        }
      ],
      "glosses": [
        "A spherical type of oak gall, produced by an oak gall wasp (tribe Cynipini)."
      ],
      "id": "en-oak_apple-en-noun-2uBswBVp",
      "links": [
        [
          "oak gall",
          "oak gall"
        ],
        [
          "tribe",
          "tribe"
        ]
      ],
      "synonyms": [
        {
          "word": "oak-apple"
        }
      ]
    }
  ],
  "word": "oak apple"
}

{
  "derived": [
    {
      "word": "Oak Apple Day"
    }
  ],
  "forms": [
    {
      "form": "oak apples",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "oak apple (plural oak apples)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with quotations",
        "Entries missing English vernacular names of taxa",
        "Entries using missing taxonomic name (tribe)",
        "Pages with 1 entry",
        "Pages with entries",
        "Quotation templates to be cleaned",
        "en:Hymenopterans",
        "en:Oaks"
      ],
      "examples": [
        {
          "ref": "1665, Robert Hooke, Micrographia, section XXV:",
          "text": "[T]he small Apples which I have often observ'd to grow on the leaves of an Oak call'd Oak-apples […] are nothing but the Matrices of an Insect, as I elsewhere show.",
          "type": "quote"
        }
      ],
      "glosses": [
        "A spherical type of oak gall, produced by an oak gall wasp (tribe Cynipini)."
      ],
      "links": [
        [
          "oak gall",
          "oak gall"
        ],
        [
          "tribe",
          "tribe"
        ]
      ]
    }
  ],
  "synonyms": [
    {
      "word": "oak-apple"
    }
  ],
  "word": "oak apple"
}