trilogy

Etymology

PIE word *tréyes From English tri- + -logy, from Latin trilogia, from Ancient Greek τριλογίᾱ (trilogíā, “trilogy”).

noun

1. A set of three works of art that are connected, and that can be seen either as a single work or as three individual works. They are commonly found in literature, film, or video games.
   22 March 2012, Scott Tobias, AV Club The Hunger Gameshttp://www.avclub.com/articles/the-hunger-games,71293/ That such a safe adaptation could come of The Hunger Games speaks more to the trilogy’s commercial ascent than the book’s actual content, which is audacious and savvy in its dark calculations.