An audiobook is a recording that is primarily of the spoken word as opposed to music. While it is often based on a recording of commercially available printed material, this is not always the case: nor is this required to fit the definition of an audiobook, which is why "audiobook" is one word rather than two. It was not intended to be descriptive of the word "book" but is rather a recorded spoken program in its own right and not necessarily an audio version of a book.
The word audiobook was established by the Audio Publishers Association, after much disagreement and wrangling, back in the 1990's. Seth Gershel, then publisher of Simon & Schuster Audio and a board member of the APA, takes confirmed credit for pushing the word forward as a necessary descriptor of the publishing output of the industry. With this easy-to-use category name in place, replacing the previous "spoken word audio," the participants in the industry agreed that they would be able to garner greater consumer publicity. "Audiobook" is now the accepted industry term.
Spoken audio was originally primarily available in school and public libraries and to a lesser extent in music shops. It was not until the 1980's that there began a concerted effort to attract book retailers. As book publishers entered the field of spoken-word publishing, the transition to book retailers carrying audiobooks became commonplace on bookshelves rather than in separate displays.
