used as an inscription on a bookplate to show the name of the book's owner
…的藏书（印在藏书者标签上显示藏书者姓名的刻印文字）：
ex libris Edith Wharton.
伊迪斯·华顿藏书。
(复同单)
a bookplate inscribed in such a way, especially a decorative one
藏书印; 藏书签。
词源
Latin, literally 'out of the books or library (of someone)'.