Where does the word ex-libris come from?

The Latin expression ex-libris is formed by the preposition ex indicating origin or provenance and the plural ablative of liber, meaning book. Its meaning would be equal to "Among the books of...", "Of the books of...", "Book of..." or "Book belonging to...". The Latin locution, as you can see, allows us to express in a single word a concept that in our language would need several words.

Are there other words for exlibris?

Even so, exlibris is not the only word for the possession mark we print on a book, although it is the most international one. In English the most common name is Bookplate, in German it is Buchzeichen, in Dutch it is Boekmerken, in French it is also called Marque de possession and in Hungarian Könyve. We will also find other names such as My book or Mein Buch.
 
The world of ex-librismo is full of words that can be used instead of exlibris, for example, to indicate the origin of the books in a library we can use ex biblioteca, ex dono, ex praemio, ex hereditate. There are also terms that serve to define the subject matter of the book collection such as: ex musicis, ex numismaticis, ex eroticis, ex philosophicis, ex poeticis or ex comicis, among others.
The ex-libris word

Ex libris, Ex Libris, Exlibris, Ex-Libris or Ex-libris?

One day a retired Latin professor came to my booth and told me that I misspelled the term "ex-libris", that Latin has never been hyphenated, and that he would like his to have only a separation between ex and libris. I told him that I had always seen it written that way, but that I would do his as he had asked. Over the years I did some research on the subject and came across this. In 1903 the Iberian Magazine initiated a survey to find out how the word ex libris should be written, among all its variants: "Ex libris", "Ex Libris", "Exlibris" or "Ex-libris". Finally it was agreed to do it with a hyphen between ex and libris. But be careful if someday you have to write ex librismo (a word used to talk about ex-libris collecting or the study of the production technique of ex-libris) or ex librista (a person who designs ex-libris, has ex-libris or collects them) remember these two words are hyphenated.

I hope that with this post you have solved all your doubts about the word ex-libris and its variants. In any case, what is clear is that with your own ex-libris you will be able to lend any volume of your collection without fear of losing it.