"fixed feast" meaning in English

{
  "forms": [
    {
      "form": "fixed feasts",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "fixed feast (plural fixed feasts)",
      "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": "topical",
          "langcode": "en",
          "name": "Christianity",
          "orig": "en:Christianity",
          "parents": [
            "Abrahamism",
            "Religion",
            "Culture",
            "Society",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "an annual celebration that is held on the same calendar date every year, such as Christmas (December 25)"
      ],
      "id": "en-fixed_feast-en-noun-5YeCGIZS",
      "links": [
        [
          "Christianity",
          "Christianity"
        ],
        [
          "annual",
          "annual"
        ],
        [
          "Christmas",
          "Christmas"
        ]
      ],
      "raw_glosses": [
        "(Christianity) an annual celebration that is held on the same calendar date every year, such as Christmas (December 25)"
      ],
      "related": [
        {
          "word": "moveable feast"
        }
      ],
      "topics": [
        "Christianity"
      ]
    }
  ],
  "word": "fixed feast"
}

{
  "forms": [
    {
      "form": "fixed feasts",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "fixed feast (plural fixed feasts)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "moveable feast"
    }
  ],
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "en:Christianity"
      ],
      "glosses": [
        "an annual celebration that is held on the same calendar date every year, such as Christmas (December 25)"
      ],
      "links": [
        [
          "Christianity",
          "Christianity"
        ],
        [
          "annual",
          "annual"
        ],
        [
          "Christmas",
          "Christmas"
        ]
      ],
      "raw_glosses": [
        "(Christianity) an annual celebration that is held on the same calendar date every year, such as Christmas (December 25)"
      ],
      "topics": [
        "Christianity"
      ]
    }
  ],
  "word": "fixed feast"
}