A bookplate phrase is a phrase or saying that is printed on a bookplate, which is a label that is placed inside the cover of a BOOK to indicate its OWNER. The two crossword solutions for the term 'bookplate phrase' are LIBRIS and OWNER. LIBRIS is a Latin word meaning 'BOOK' and OWNER is someone who has possession of something. Therefore, a bookplate phrase is a phrase or saying that is printed on a bookplate to indicate the ownership of the BOOK.