A series of three dramas which, although each of them is in one sense complete, have a close mutual relation, and form one historical and poetical picture. Shakespeare's " Henry VI." is an example.
a group of three films that together compose a larger narrative and are related in subject or theme Examples: Coppola's three Godfather films, the Terminator films trilogy, Terry Gilliam's 'Age of Reason' trilogy, Satyajit Ray's Apu trilogy, the Lord of the Rings trilogy, Ingmar Bergman's trilogy, the Qatsi trilogy, Spielberg's 'Indiana Jones' films, the original Star Wars trilogy, and Kieslowski's 'Three Colors' films
Three plays performed in sequence; the basic pattern of ancient Greek tragedies, of which one - Aeschylus' The Oresteia ( Agamemnon, The Libation Bearers, and The Eumenides) - is still extant.