Megabook is often used to describe a large or substantial book that contains an abundance of information. However, there are several synonyms that can be used to describe such books. Encyclopedic book, tome, compendium, or opus are all good alternatives to the term megabook. These words convey a sense of size and depth, suggesting that the book contains a wealth of knowledge and information. Other synonyms that could be used include magnum opus, masterwork, and encyclopedia. No matter which word is chosen to replace megabook, the implication remains clear that an extensive collection of information lies within those pages.