dilogy

From Latin dilogia, from Ancient Greek διλογία (dilogía, “repetition”), from δίς (dís, “twice”) + -λογία (-logía, “-logy”)

dilogy (countable and uncountable, plural dilogies)

1. Ambiguous or equivocal speech or discourse.
2. Repetition of a word or phrase.
3. (countable, nonstandard) A series of two related works.
   • 1885, The Journal of Hellenic studies: Volume 6, page 167

     why tragedy took the form of a trilogy — not a dilogy, tetralogy, or single drama

   • 1983, Studies in Aeschylus, Reginald Pepys Winnington-Ingram, page 189

     another school of thought, for which Purphoros is a mirage, a mere doublet of Purkaeus, and there were never more than two linked Prometheus plays -- as it were a dilogy

   • 2012, A New Companion to the Gothic, David Punter, Page 71

     Most notable of these are his “dilogy” The Salamander (1841) and The Cosmorama (1839)

• (two related works): duology (nonstandard)

• trilogy (3)
• tetralogy (4)
• pentalogy (5)
• hexalogy (6)
• heptalogy (7)
• octalogy (8)
• ennealogy (9)
• decalogy (10)
• polylogy (2+)