dichotomy, duality(noun)

being twofold; a classification into two opposed parts or subclasses

"the dichotomy between eastern and western culture"

duality, wave-particle duality(noun)

(physics) the property of matter and electromagnetic radiation that is characterized by the fact that some properties can be explained best by wave theory and others by particle theory

duality(noun)

(geometry) the interchangeability of the roles of points and planes in the theorems of projective geometry

duality(Noun)

A classification into two subclasses or opposed parts.

duality(Noun)

The interchangeability of points and planes.

duality(Noun)

The mathematical equivalence of two seemingly different theoretical descriptions of a physical system.

Duality(noun)

the quality or condition of being two or twofold; dual character or usage