tetralogy

• POS: Noun
• HYPHEN: te=tral=o=gy

CIDE DICTIONARY

tetralogy, n. [Gr. ; te`tra- (see Tetra-) + a speech, discourse: cf. F. tétralogie.].

 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.  [1913 Webster]
" A group or series of three tragedies, exhibited together without a fourth piese, was called a trilogy."  [1913 Webster]

OXFORD DICTIONARY

tetralogy, n. (pl. -ies)
1 a group of four related literary or operatic works.
2 Gk Antiq. a trilogy of tragedies with a satyric drama.