"semiquincentennial" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "semi-",
        "3": "quincentennial"
      },
      "expansion": "semi- + quincentennial",
      "name": "af"
    }
  ],
  "etymology_text": "From semi- + quincentennial.",
  "forms": [
    {
      "form": "semiquincentennials",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "semiquincentennial (plural semiquincentennials)",
      "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"
        },
        {
          "kind": "other",
          "name": "English terms prefixed with semi-",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English terms suffixed with -ennial",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "text": "The year 2026 will mark the semiquincentennial of the founding of the United States.",
          "type": "example"
        }
      ],
      "glosses": [
        "A 250th anniversary."
      ],
      "id": "en-semiquincentennial-en-noun-RLV7nnjY",
      "links": [
        [
          "anniversary",
          "anniversary"
        ]
      ],
      "synonyms": [
        {
          "word": "sestercentennial"
        }
      ]
    }
  ],
  "word": "semiquincentennial"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "semi-",
        "3": "quincentennial"
      },
      "expansion": "semi- + quincentennial",
      "name": "af"
    }
  ],
  "etymology_text": "From semi- + quincentennial.",
  "forms": [
    {
      "form": "semiquincentennials",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "semiquincentennial (plural semiquincentennials)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English nouns",
        "English terms prefixed with semi-",
        "English terms suffixed with -ennial",
        "English terms with usage examples",
        "Pages with 1 entry"
      ],
      "examples": [
        {
          "text": "The year 2026 will mark the semiquincentennial of the founding of the United States.",
          "type": "example"
        }
      ],
      "glosses": [
        "A 250th anniversary."
      ],
      "links": [
        [
          "anniversary",
          "anniversary"
        ]
      ],
      "synonyms": [
        {
          "word": "sestercentennial"
        }
      ]
    }
  ],
  "word": "semiquincentennial"
}