Te*tral"o*gy (?), n. [Gr. ; (see Tetra-) + a speech, discourse: cf. F. t'etralogie.] Gr. Drama
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.
⇒ A group or series of three tragedies, exhibited together without a fourth piece, was called a trilogy.
© Webster 1913.