From The Art and Popular Culture Encyclopedia
Dime novel, though it has a specific meaning, has also become a catch-all term for several different (but related) forms of late 19th century and early 20th century U.S. popular fiction, including “true” dime novels, story papers, five and ten cent weekly libraries, “thick book” reprints and sometimes even early pulp magazines. The English equivalents were generally called penny dreadfuls or shilling shockers. American firms also issued foreign editions of many of their works, especially as series characters came into vogue. The term was being used as late as 1940, in the short lived pulp Western Dime Novels. Dime novels, in spirit at least, are the antecedent of today’s mass market paperbacks, comic books, and some would say television and movies. In the modern age, "dime novel" has become a term to describe any quickly-written, lurid potboiler.