"octocentenary" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "octo",
        "3": "centenary"
      },
      "expansion": "octo- + centenary",
      "name": "prefix"
    }
  ],
  "etymology_text": "From octo- + centenary.",
  "forms": [
    {
      "form": "octocentenaries",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "octocentenary (plural octocentenaries)",
      "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 octo-",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "An eight-hundredth anniversary."
      ],
      "id": "en-octocentenary-en-noun-G1qzM5gI",
      "links": [
        [
          "eight",
          "eight"
        ],
        [
          "hundredth",
          "hundredth"
        ],
        [
          "anniversary",
          "anniversary"
        ]
      ],
      "related": [
        {
          "word": "octingentenary"
        },
        {
          "word": "octocentennial"
        }
      ]
    }
  ],
  "word": "octocentenary"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "octo",
        "3": "centenary"
      },
      "expansion": "octo- + centenary",
      "name": "prefix"
    }
  ],
  "etymology_text": "From octo- + centenary.",
  "forms": [
    {
      "form": "octocentenaries",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "octocentenary (plural octocentenaries)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "octingentenary"
    },
    {
      "word": "octocentennial"
    }
  ],
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English nouns",
        "English terms prefixed with octo-",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "glosses": [
        "An eight-hundredth anniversary."
      ],
      "links": [
        [
          "eight",
          "eight"
        ],
        [
          "hundredth",
          "hundredth"
        ],
        [
          "anniversary",
          "anniversary"
        ]
      ]
    }
  ],
  "word": "octocentenary"
}