trilogy

/ˈtɹɪlədʒi/

IPA: /T R IH1 L AH0 JH IY0/

noun
  1. 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.

Source: https://en.wiktionary.org/wiki/trilogy