TRILOGY

trilogy

(noun) a set of three literary or dramatic works related in subject or theme

Source: WordNet® 3.1

Etymology

Noun

trilogy (plural trilogies)

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: Wiktionary

Tril"o*gy, n. Etym: [Gr. Tri-) + trilogie.]

Definition: 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. On the Greek stage, a drama, or acted story, consisted in reality of three dramas, called together a trilogy, and performed consecutively in the course of one day. Coleridge.

Source: Webster’s Unabridged Dictionary 1913 Edition