Indie is a term applied to a self-published author. It is short for independent literature.
The emergence of eBooks and eBook tools has meant that a new author can create his or her own book and sell it. Some retailers like Barnes and Noble and Amazon have recognized this trend and will accept eBooks from Indie authors directly. Other publishers have focused on attracting the author or supplying tools to aid in the publication. This trend has changed the entire publishing arena in so far as eBooks are concerned. There are also on-demand printing companies that will support regular book versions for these authors also.