Indie or independent RPG publishing is hard to define, as the industry itself is not a mainstream publishing category. Generally speaking, it tends to mean anything not published by the current publisher of Dungeons & Dragons or the publisher of other major fads, such as Vampire: The Masquerade. In many cases, it is used to refer to small self-publishing businesses that do not rely on licensing other products, but in comparison to the wider culture, almost any RPG business would be considered a small, independent publisher, with the exception of Wizards of the Coast, a subsidiary of Hasbro.
Indie as an aesthetic[]
By virtue of their origins, indie RPGs are very diverse. This means that many of them handle role-playing in ways that differ substantially from traditional games, including mechanical innovations, thematic focuses (especially if something other than combat, intrigue, and exploration), a tendency toward more story-based design, and often a focused or niche game format. This is purely a stereotype; an indie game can certainly be a traditional fantasy game focused on combat, intrigue, and exploration using mostly a success-failure resolution system.