duality
Americannoun
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a dual state or quality.
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Mathematics. a symmetry within a mathematical system such that a theorem remains valid if certain objects, relations, or operations are interchanged, as the interchange of points and lines in a plane in projective geometry.
noun
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the state or quality of being two or in two parts; dichotomy
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physics the principle that a wave-particle duality exists in microphysics in which wave theory and corpuscular theory are complementary. The propagation of electromagnetic radiation is analysed using wave theory but its interaction with matter is described in terms of photons. The condition of particles such as electrons, neutrons, and atoms is described in terms of de Broglie waves
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geometry the interchangeability of the roles of the point and the plane in statements and theorems in projective geometry
Other Word Forms
- nonduality noun
Etymology
Origin of duality
1350–1400; Middle English dualitie < Late Latin duālitās. See dual, -ity
Explanation
As hinted at by the word "dual" within it, duality refers to having two parts, often with opposite meanings, like the duality of good and evil. If there are two sides to a coin, metaphorically speaking, there's a duality. Peace and war, love and hate, up and down, and black and white are dualities. Another term for a duality is a dichotomy. Duality has technical meanings in geometry and physics. In geometry, duality refers to how points and planes have interchangeable roles in projective geometry. In physics, duality is the property of matter and electromagnetic radiation to be understood best through wave theory or particle theory.
Vocabulary lists containing duality
It Takes Two: Di
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UCPS 6th Grade Roots List #5
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Dig
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Conscious feelings are one of its techniques, emerging “deep in the subcortical regions” where the brain’s interoceptive neurons receive messages from the body and Cartesian duality dissolves.
From The Wall Street Journal • Mar. 15, 2026
Perhaps highlighting how the theme of duality runs deep even within Requiem's team itself, Kawata says how despite this, the team have still brought "something new to the table" with their latest offering.
From BBC • Feb. 27, 2026
Li describes the finding as part of what he calls a "new duality."
From Science Daily • Nov. 9, 2025
Bringing that duality introduced a style that was both fresh and ancestral into a pop music scene still defined by the electronic splash of New Jack Swing artists like Boyz II Men, Saadiq’s group Tony!
From Salon • Oct. 19, 2025
The number-shape duality in Greek numbers made it easy; after all, zero didn’t have a shape and could thus not be a number.
From "Zero: The Biography of a Dangerous Idea" by Charles Seife
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
