https://en.wikipedia.org/wiki/Trilogy
A trilogy is a set of three distinct works that are connected and can be seen either as a single work or as three individual works. They are commonly found in literature, film, and video games. Three-part works that are considered components of a larger work also exist, such as the triptych or the three-movement sonata, but they are not commonly referred to with the term "trilogy".
Most trilogies are works of fiction involving the same characters or setting, such as The Deptford Trilogy of novels by Robertson Davies, The Apu Trilogy of films by Satyajit Ray, and The Kingdom Trilogy of television miniseries from 1994 to 2022 by Lars von Trier. Other fiction trilogies are connected only by theme: for example, each film of Krzysztof Kieślowski's Three Colours trilogyexplores one of the political ideals of the French Republic (liberty, equality, fraternity). Trilogies can also be connected in less obvious ways, such as The Nova Trilogy of novels by William S. Burroughs, each written using cut-up technique.