tetralogy

A series of four related dramatic, operatic, or literary works.

A complex of four symptoms.

A group of four dramatic compositions, three tragic and one satyric, which were exhibited in connection on the Athenian stage for the prize at the festivals of Bacchus.

A group or series of four dramatic pieces, three tragedies and one satyric, or comic, piece (or sometimes four tragedies), represented consequently on the Attic stage at the Dionysiac festival.

A set of four works of art that are connected, and that can be seen either as a single work or as four individual works. They are commonly found in literature, film, or video games.