"sacred harp" meaning in English

{
  "etymology_text": "From the name of a songbook first published in 1844, The Sacred Harp.",
  "head_templates": [
    {
      "args": {
        "1": "-"
      },
      "expansion": "sacred harp (uncountable)",
      "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": "Musical genres",
          "orig": "en:Musical genres",
          "parents": [
            "Genres",
            "Music",
            "Entertainment",
            "Art",
            "Sound",
            "Culture",
            "Energy",
            "Society",
            "Nature",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A genre of Christian music based on shape-note singing."
      ],
      "id": "en-sacred_harp-en-noun-jLs4J5I1",
      "links": [
        [
          "music",
          "music"
        ],
        [
          "genre",
          "genre"
        ],
        [
          "Christian",
          "Christian"
        ],
        [
          "shape-note",
          "shape note"
        ]
      ],
      "raw_glosses": [
        "(music) A genre of Christian music based on shape-note singing."
      ],
      "synonyms": [
        {
          "word": "Sacred Harp"
        }
      ],
      "tags": [
        "uncountable"
      ],
      "topics": [
        "entertainment",
        "lifestyle",
        "music"
      ],
      "wikipedia": [
        "Sacred Harp"
      ]
    }
  ],
  "word": "sacred harp"
}

{
  "etymology_text": "From the name of a songbook first published in 1844, The Sacred Harp.",
  "head_templates": [
    {
      "args": {
        "1": "-"
      },
      "expansion": "sacred harp (uncountable)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English uncountable nouns",
        "en:Musical genres"
      ],
      "glosses": [
        "A genre of Christian music based on shape-note singing."
      ],
      "links": [
        [
          "music",
          "music"
        ],
        [
          "genre",
          "genre"
        ],
        [
          "Christian",
          "Christian"
        ],
        [
          "shape-note",
          "shape note"
        ]
      ],
      "raw_glosses": [
        "(music) A genre of Christian music based on shape-note singing."
      ],
      "tags": [
        "uncountable"
      ],
      "topics": [
        "entertainment",
        "lifestyle",
        "music"
      ],
      "wikipedia": [
        "Sacred Harp"
      ]
    }
  ],
  "synonyms": [
    {
      "word": "Sacred Harp"
    }
  ],
  "word": "sacred harp"
}