"courtesy book" meaning in English

{
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    {
      "form": "courtesy books",
      "tags": [
        "plural"
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  "head_templates": [
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      "expansion": "courtesy book (plural courtesy books)",
      "name": "en-noun"
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  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
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          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
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      "glosses": [
        "A didactic manual of knowledge for courtiers, explaining matters of etiquette, morality, and socially acceptable behavior."
      ],
      "id": "en-courtesy_book-en-noun-nB1PYGNi",
      "links": [
        [
          "didactic",
          "didactic"
        ],
        [
          "manual",
          "manual"
        ],
        [
          "knowledge",
          "knowledge"
        ],
        [
          "courtier",
          "courtier"
        ],
        [
          "etiquette",
          "etiquette"
        ],
        [
          "morality",
          "morality"
        ]
      ],
      "raw_glosses": [
        "(historical) A didactic manual of knowledge for courtiers, explaining matters of etiquette, morality, and socially acceptable behavior."
      ],
      "tags": [
        "historical"
      ]
    }
  ],
  "word": "courtesy book"
}

{
  "forms": [
    {
      "form": "courtesy books",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "courtesy book (plural courtesy books)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with historical senses",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "glosses": [
        "A didactic manual of knowledge for courtiers, explaining matters of etiquette, morality, and socially acceptable behavior."
      ],
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        [
          "didactic",
          "didactic"
        ],
        [
          "manual",
          "manual"
        ],
        [
          "knowledge",
          "knowledge"
        ],
        [
          "courtier",
          "courtier"
        ],
        [
          "etiquette",
          "etiquette"
        ],
        [
          "morality",
          "morality"
        ]
      ],
      "raw_glosses": [
        "(historical) A didactic manual of knowledge for courtiers, explaining matters of etiquette, morality, and socially acceptable behavior."
      ],
      "tags": [
        "historical"
      ]
    }
  ],
  "word": "courtesy book"
}