I thought Id posted on this before, but Google disagrees. Apologies to anyone who has heard it before.
The internet Classics list has been discussing how to say Ex Libris in Greek, which reminded me (as so many things do) of something else only tangentially related. A friend once gave me a book that already had his bookplate in it, since hed gotten a new, unthumbed copy for Christmas and no one really needs two copies of Greek Mathematical Thought and the Origins of Algebra. As a joke, I added a single Latin word before Ex Libris. As far as I was able which was pretty far I used exactly the same font and color as the printed bookplate. What was that word? Surreptus, of course.