Where does the word "masochism" come from, and how did it work its way into popular usage?

Uh, yeah, it's another eponym, by way of a dude named Masoch, sometimes praised as rather an artiste where de Sade is, by some accounts, fundamentally just a bully.

Leopold von Sacher-Masoch wrote a book called "Venus in Furs" in 1870. A sadomasochistic relationship in which a masochistic man falls in love with a sadistic woman defines masochism and separates it from sadism.