"off book" meaning in English

{
  "antonyms": [
    {
      "word": "on book"
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "prepositional phrase",
        "head": ""
      },
      "expansion": "off book",
      "name": "head"
    },
    {
      "args": {},
      "expansion": "off book",
      "name": "en-PP"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "prep_phrase",
  "related": [
    {
      "_dis1": "0 0",
      "word": "off-book"
    }
  ],
  "senses": [
    {
      "categories": [
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Theater",
          "orig": "en:Theater",
          "parents": [
            "Art",
            "Entertainment",
            "Culture",
            "Society",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "text": "After 5 days studying the script, Jane is now off book, and can concentrate on gesture more.",
          "type": "example"
        },
        {
          "ref": "1873, Thomas Wright, Our New Masters, Strahan & Co., page 125:",
          "text": "\"He will glibly parse a sentence ... and repeat the catechism and whole chapters of the Bible 'off book.'\"",
          "type": "quote"
        },
        {
          "ref": "1993, Doug Moston, Coming to Terms with Acting, →ISBN, page 74:",
          "text": "\"In all likelihood, the director will leave you alone throughout the rest of the production and focus attention on the guy who isn't off book yet.\"",
          "type": "quote"
        },
        {
          "ref": "2003, Jeffrey Eugenides, Middlesex, Picador,, →ISBN, page 332:",
          "text": "\"'So if Antigone wants to be off book, I think the rest of you should be off book too.'\"",
          "type": "quote"
        }
      ],
      "glosses": [
        "No longer needing the script to rehearse."
      ],
      "id": "en-off_book-en-prep_phrase-FFy2zhpQ",
      "links": [
        [
          "theater",
          "theater"
        ],
        [
          "script",
          "script"
        ],
        [
          "rehearse",
          "rehearse"
        ]
      ],
      "raw_glosses": [
        "(theater) No longer needing the script to rehearse."
      ],
      "topics": [
        "entertainment",
        "lifestyle",
        "theater"
      ]
    },
    {
      "categories": [
        {
          "_dis": "3 97",
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w+disamb"
        },
        {
          "_dis": "6 94",
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w+disamb"
        },
        {
          "_dis": "2 98",
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w+disamb"
        }
      ],
      "examples": [
        {
          "ref": "1963, Richard Austin Smith, Corporations in Crisis, Doubleday, page 74:",
          "text": "\"in the winter of 1957-58 prices were 60 percent off book.\"",
          "type": "quote"
        }
      ],
      "glosses": [
        "below the list price"
      ],
      "id": "en-off_book-en-prep_phrase-QP4H9iMW",
      "links": [
        [
          "list price",
          "list price"
        ]
      ]
    }
  ],
  "word": "off book"
}

{
  "antonyms": [
    {
      "word": "on book"
    }
  ],
  "categories": [
    "English entries with incorrect language header",
    "English lemmas",
    "English multiword terms",
    "English prepositional phrases",
    "Pages with 1 entry",
    "Pages with entries"
  ],
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "prepositional phrase",
        "head": ""
      },
      "expansion": "off book",
      "name": "head"
    },
    {
      "args": {},
      "expansion": "off book",
      "name": "en-PP"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "prep_phrase",
  "related": [
    {
      "word": "off-book"
    }
  ],
  "senses": [
    {
      "categories": [
        "English terms with quotations",
        "English terms with usage examples",
        "en:Theater"
      ],
      "examples": [
        {
          "text": "After 5 days studying the script, Jane is now off book, and can concentrate on gesture more.",
          "type": "example"
        },
        {
          "ref": "1873, Thomas Wright, Our New Masters, Strahan & Co., page 125:",
          "text": "\"He will glibly parse a sentence ... and repeat the catechism and whole chapters of the Bible 'off book.'\"",
          "type": "quote"
        },
        {
          "ref": "1993, Doug Moston, Coming to Terms with Acting, →ISBN, page 74:",
          "text": "\"In all likelihood, the director will leave you alone throughout the rest of the production and focus attention on the guy who isn't off book yet.\"",
          "type": "quote"
        },
        {
          "ref": "2003, Jeffrey Eugenides, Middlesex, Picador,, →ISBN, page 332:",
          "text": "\"'So if Antigone wants to be off book, I think the rest of you should be off book too.'\"",
          "type": "quote"
        }
      ],
      "glosses": [
        "No longer needing the script to rehearse."
      ],
      "links": [
        [
          "theater",
          "theater"
        ],
        [
          "script",
          "script"
        ],
        [
          "rehearse",
          "rehearse"
        ]
      ],
      "raw_glosses": [
        "(theater) No longer needing the script to rehearse."
      ],
      "topics": [
        "entertainment",
        "lifestyle",
        "theater"
      ]
    },
    {
      "categories": [
        "English terms with quotations",
        "Quotation templates to be cleaned"
      ],
      "examples": [
        {
          "ref": "1963, Richard Austin Smith, Corporations in Crisis, Doubleday, page 74:",
          "text": "\"in the winter of 1957-58 prices were 60 percent off book.\"",
          "type": "quote"
        }
      ],
      "glosses": [
        "below the list price"
      ],
      "links": [
        [
          "list price",
          "list price"
        ]
      ]
    }
  ],
  "word": "off book"
}