duality

Estimated CEFR level: C2 — Proficiency

Estimated from word frequency; not an official CEFR classification.

Definition

noun being twofold; a classification into two opposed parts or subclasses
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
noun (geometry) the interchangeability of the roles of points and planes in the theorems of projective geometry

From Latin duālitās. From dual + -ity.

There is a duality in man. — My Reminiscences, Rabindranath Tagore
In any circumstances, he was always insisting on his duality. — The Life of Sir Richard Burton, Thomas Wright
But this duality of intuition Kant neither would nor could admit. — Creative Evolution, Bergson, Henri

dichotomy

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