v. Present participle of book.n. The act or process of writing something down in (a) book(s), e.g. in accountingn. A reservation for a service, such as accommodation in an hotel.n. The engagement of a performer for a particular performance.n. The issuing of a caution which is usually written down in a book, and results in a yellow card or (after two bookings) a red card, that is to say, the player is sent from the field of play.n. The process of photographing, fingerprinting and recording identifying data of a suspect following arrest.