E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Trilogy.
A group of three tragedies. Everyone in Greece who took part in the poetic contest had to produce a trilogy and a satyric drama. We have only one specimen, and that is by Æschylos, embracing the Agamemnon, the Chophor, and the Eumenids.