Answer: trilogies

AnswerCrossword Clue
TRILOGIESTolkien's "Lord of the Rings" and Dos Passos's "U.S.A."
TRILOGIESCertain literary works.
TRILOGIES"Studs Lonigan" and others
trilogiesA group or series of three related things
trilogies(in ancient Greece) A series of three tragedies performed one after the other
trilogiesA group of three related novels, plays, films, operas, or albums
trilogiesTRILOGY, a group of three related literary works