being twofold; a classification into two opposed parts or subclasses
The dichotomy between eastern and western culture.
source: WordNet 3.0
(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
source: WordNet 3.0
(geometry) the interchangeability of the roles of points and planes in the theorems of projective geometry
source: WordNet 3.0
The quality or condition of being two or twofold; dual character or usage.