Definition of "book"
book1
/bʊk/
noun
plural books
(figurative) Any source of instruction.
book2
/bʊk/
verb
third-person singular simple present books, present participle booking, simple past and past participle booked
plural books
(figurative) Any source of instruction.
third-person singular simple present books, present participle booking, simple past and past participle booked