duology

As nouns the difference between duology and null

is that duology is (nonstandard) a series comprised of two parts, particularly in genre fiction while null is zero, nil; the cardinal number before einn.

As a letter s

is the letter s with a.

As a noun duology is

(nonstandard) a series comprised of two parts, particularly in genre fiction.

As a noun duology

is (nonstandard) a series comprised of two parts, particularly in genre fiction.

As an adjective undefined is

lacking a definition or value.

As a noun duology

is (nonstandard) a series comprised of two parts, particularly in genre fiction.

As a verb series is

.

As nouns the difference between sequel and duology

is that sequel is (narratology) a narrative that is written after another narrative set in the same universe, especially a narrative that is chronologically set after its predecessors, or (perhaps improper usage) any narrative that has a preceding narrative of its own while duology is (nonstandard) a series comprised of two parts, particularly in genre fiction.

As nouns the difference between trilogy and duology

is that trilogy is a set of three works of art that are connected, and that can be seen either as a single work or as three individual works. They are commonly found in literature, film, or video games while duology is a series comprised of two parts, particularly in genre fiction.