An advance copy, also known as an advance reading copy or ARC, is a copy of a book released by its publisher before the book has gone to press for a complete printing. ARCs generally do not have the final dust jacket, formatting or binding of the finished product; the text of an ARC may also differ from that of the published book if the book is edited after the ARC is produced. ARCs are normally distributed to reviewers, bookstores, magazines, and (in some cases) libraries between three and six months before the book is officially released.
P.S. LOL , I know what you mean about needing a dictionary for the Accronyms!