A novella is a short novel, that is, a work of narrative prose fiction that is shorter than most novels but longer than most short stories. The Writers of America organization in the United States defines a novella as having a word count of between 17,500 and 40,000 words. In Britain, the British Library website describes novellas as being "between 7,500 and 10,000 words long". In Australia, the Australian Government Publishing Service website describes novellas as being "about 20,000 words long". In terms of genre classification, novellas are considered to be part of the mystery or crime category on bookstore shelves in both the United States and Canada. The term "novella" comes from the Latin word for ninth, which refers to the fact that these narratives were originally published in books consisting of nine leaves or pages. Today, however, a chapter from a larger work may be labeled as a novella if it falls within this length requirement. For example, Charles Dickens' 1866 novel A Tale of Two Cities is approximately 600 pages long. However, since it is estimated that there are about 80,000 words in a page, this work would be defined as a novella by many publishers. Novellas have been important elements in American literature since their introduction in the early 19th century.