"Reformation Sunday" meaning in English

{
  "head_templates": [
    {
      "args": {},
      "expansion": "Reformation Sunday",
      "name": "en-proper noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "name",
  "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 entries with topic categories using raw markup",
          "parents": [
            "Entries with topic categories using raw markup",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English terms with non-redundant non-automated sortkeys",
          "parents": [
            "Terms with non-redundant non-automated sortkeys",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Holidays",
          "orig": "en:Holidays",
          "parents": [
            "Observances",
            "Calendar",
            "Timekeeping",
            "Time",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Protestantism",
          "orig": "en:Protestantism",
          "parents": [
            "Christianity",
            "Abrahamism",
            "Religion",
            "Culture",
            "Society",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "In Protestant churches, a commemoration of Martin Luther's 95 Theses, observed on the last Sunday in October."
      ],
      "id": "en-Reformation_Sunday-en-name-VM-ZeDwu",
      "links": [
        [
          "October",
          "October"
        ]
      ],
      "wikipedia": [
        "Reformation Sunday"
      ]
    }
  ],
  "word": "Reformation Sunday"
}

{
  "head_templates": [
    {
      "args": {},
      "expansion": "Reformation Sunday",
      "name": "en-proper noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "name",
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English entries with topic categories using raw markup",
        "English lemmas",
        "English multiword terms",
        "English proper nouns",
        "English terms with non-redundant non-automated sortkeys",
        "English uncountable nouns",
        "en:Holidays",
        "en:Protestantism"
      ],
      "glosses": [
        "In Protestant churches, a commemoration of Martin Luther's 95 Theses, observed on the last Sunday in October."
      ],
      "links": [
        [
          "October",
          "October"
        ]
      ],
      "wikipedia": [
        "Reformation Sunday"
      ]
    }
  ],
  "word": "Reformation Sunday"
}