Here dilogy is defined as "a series of two related works". I can't shake off the feeling that there is a more commonly used word for this. Is there? If yes, what is it?


5 Answers 5


A duology is a pair of related novels, plays or films.

  • 1
    +1 to this because it's what popped into my mind, and is the most likely one of the answers so far a layperson will both recognize as a word and understand the meaning of (do to the prevalence of "trilogy")
    – Izkata
    Nov 12, 2012 at 3:29

"diptych", sense 3 : a work made up of two matching parts (ref: Merriam-Webster).


Two works do not a series make. In fact, two of anything do not a series make.

Carlo, however, has the correct answer here: it’s a diptych, which is like a triptych but with two pieces instead of three. Wikipedia has a brief article on it.

Here is more about its etymology, from the OED:

Latin diptycha (pl.), a. late Greek δίπτυχα pair of writing-tablets, neut. pl. of δίπτυχος double-folded, f. δι-, δίς twice + πτυχή fold. Cf. mod. French diptyque, C. 1700 in Hatz.-Darm.

Diptych does enjoy some currency as a work comprising two halves. For example:

The 2nd, and darker portion, of this volume devotes most of its space to lamentations for the poets estranged daughter, for his deceased parents, and for a enigmatic hell-raiser of a perplexing but beloved cat, a very human quadruped. — Diptych: Voyage to Ernie Spirit, Swell a Large Lament and Other Fictions

Furthermore, award-winning author Dan Simmons often refers to his two-volume stories as diptychs, such as the Ilium and Olympos pair. For example, from Dan’s own website:

Page 284 This long quote from Marcel Proust–which figures twice in the text, here and on page 459–comes from LE CÔTÉ DE GUERMANTES. This might be the crux of the ILIUM/OLYMPOS diptych, if not of Dan’s entire œuvre.

And it’s not just Simmons. Here is one critic writing about another pair of novels of Dan’s:

[A] Simmons fan will note that a similar problem affected the Endymion diptych: The first volume wasn’t terribly useful, but the second one was the whole point of the setup. — [citation]

  • In Art History, both diptych and especially triptych are used to refer to two or three panels or leaves of a painted work. I have seen diptych used to describe two related works of fiction by the same author, though it isn't common. The reason it isn't common is because it isn't standard usage in publishing or literature to refer to two books as a series. Ouvre might work if both were published as one volume, but that's more formal and should be used with care so as to avoid pretense. Nov 12, 2012 at 10:49
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    @FeralOink: If you mean oeuvre, it's more commonly used to refer to a writer's total output; best avoided, if only to reduce confusion. Nov 12, 2012 at 14:23
  • @TimLymington Yes, yes! That is what I meant! Oeuvre, as a body of work. If the entire output were two works, then it could be used, but that is unlikely and rather a special case. Thank you! Nov 13, 2012 at 14:33

Dyad is commonly used for pairs of things. Here is a dyad of definitions:

There's a whole set of related words with increasing valence: monad, dyad, triad, tetrad, pentad, hexad, etc.

  • The second definition is a great resource, however, it explicitly states that it uses Webster's 1828 and 1913 versions, and doesn't contain modern usages of language. The first link is good, but it confirmed my impression that dyad is used for two of something in chemistry or astronomy etc., with no explicit mention of two books or works of literature. Nov 12, 2012 at 10:56
  • @Feral: Sure, for literature I'd go with the more specific duology, but the original question does not expressly mention books or works of literature. Nov 12, 2012 at 14:00
  • Yes, I did mean literature, but did not mention it in the question, so you are quite right. Nov 12, 2012 at 23:25

A common pair of words in usage is prequel and sequel.

  • That would require a third work in-between.
    – RegDwigнt
    Nov 12, 2012 at 11:10
  • I do not think that that word means what you think it means.
    – tchrist
    Nov 12, 2012 at 15:17
  • @RegDwighт: I agree, good point!
    – Sayan
    Nov 14, 2012 at 10:41

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