"blue book" meaning in English

{
  "etymology_text": "The term dates back to the 15th century, when large blue velvet-covered books were used for record-keeping by the Parliament of the United Kingdom.",
  "forms": [
    {
      "form": "blue books",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "blue book (plural blue books)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [],
      "examples": [
        {
          "ref": "1912, Arthur Conan Doyle, The Lost World […], London; New York, N.Y.: Hodder and Stoughton, →OCLC:",
          "text": "\"I was the flail of the Lord up in those parts, I may tell you, though you won't find it in any Blue-book.\"",
          "type": "quote"
        }
      ],
      "glosses": [
        "A book of statistics or almanac, usually published by an agency or as a trade publication."
      ],
      "id": "en-blue_book-en-noun-QeefMto-",
      "links": [
        [
          "statistics",
          "statistics"
        ],
        [
          "almanac",
          "almanac"
        ]
      ]
    },
    {
      "categories": [
        {
          "_dis": "42 58",
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w+disamb"
        },
        {
          "_dis": "33 67",
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w+disamb"
        },
        {
          "_dis": "15 85",
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w+disamb"
        }
      ],
      "glosses": [
        "Used other than figuratively or idiomatically: see blue, book."
      ],
      "id": "en-blue_book-en-noun-cVOZ2Nvh",
      "links": [
        [
          "blue",
          "blue#English"
        ],
        [
          "book",
          "book#English"
        ]
      ],
      "related": [
        {
          "_dis1": "36 64",
          "word": "Project Blue Book"
        },
        {
          "_dis1": "36 64",
          "word": "blue book exam"
        }
      ]
    }
  ],
  "word": "blue book"
}

{
  "categories": [
    "English countable nouns",
    "English entries with incorrect language header",
    "English lemmas",
    "English multiword terms",
    "English nouns",
    "Pages with 1 entry",
    "Pages with entries"
  ],
  "etymology_text": "The term dates back to the 15th century, when large blue velvet-covered books were used for record-keeping by the Parliament of the United Kingdom.",
  "forms": [
    {
      "form": "blue books",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "blue book (plural blue books)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "related": [
    {
      "word": "Project Blue Book"
    },
    {
      "word": "blue book exam"
    }
  ],
  "senses": [
    {
      "categories": [
        "English terms with quotations"
      ],
      "examples": [
        {
          "ref": "1912, Arthur Conan Doyle, The Lost World […], London; New York, N.Y.: Hodder and Stoughton, →OCLC:",
          "text": "\"I was the flail of the Lord up in those parts, I may tell you, though you won't find it in any Blue-book.\"",
          "type": "quote"
        }
      ],
      "glosses": [
        "A book of statistics or almanac, usually published by an agency or as a trade publication."
      ],
      "links": [
        [
          "statistics",
          "statistics"
        ],
        [
          "almanac",
          "almanac"
        ]
      ]
    },
    {
      "glosses": [
        "Used other than figuratively or idiomatically: see blue, book."
      ],
      "links": [
        [
          "blue",
          "blue#English"
        ],
        [
          "book",
          "book#English"
        ]
      ]
    }
  ],
  "word": "blue book"
}