duality

1. The quality of containing or comprising two often opposed parts or aspects. (countable, uncountable) · the moral duality of certain characters· Mother Nature's eternal duality, both life-giving and destructive
2. The aggregate of two complementary subclasses or parts. (countable, uncountable) · philosophical duality· The novel explored the duality of good and evil.
3. The mathematical equivalence of two seemingly different theoretical descriptions of a physical system. (countable, uncountable) · wave-particle duality
4. The interchangeability of points and planes. (countable, uncountable)

Plural dualities