Book/bʊk/ Definition 1 of 6Pro Tip 1/3Literal and Figurative The word 'book' can be used to discuss actual physical books or ideas and experiences metaphorically. He wrote the book on engineering. Pro Tip 2/3Genre Specific Certain expressions with 'book' may suggest specific genres, like a 'recipe book' for cooking. She published a comic book. Pro Tip 3/3Cultural Significance 'Book' can imply authority and knowledge, often respected in many cultures. The book has been passed down for generations.