Duality - Definition
duality
n 1: being twofold; a classification into two opposed parts or
subclasses; "the dichotomy between eastern and western
culture" [syn: dichotomy, duality]
2: (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 [syn: duality, wave-particle duality]
3: (geometry) the interchangeability of the roles of points and
planes in the theorems of projective geometry