trilogy Meaning, Definition & Usage

  1. noun a set of three literary or dramatic works related in subject or theme

WordNet

Tril"o*gy noun
Etymology
Gr. pref. (see Tri-) + speech, discourse: cf. F. trilogie.
Definitions
  1. 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.

Webster 1913