duality
Americannoun
-
a dual state or quality.
-
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
-
the state or quality of being two or in two parts; dichotomy
-
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
-
geometry the interchangeability of the roles of the point and the plane in statements and theorems in projective geometry
Other Word Forms
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
Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!
UCPS 6th Grade Roots List #5
Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!
Dig
Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!
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.
The man’s duality was evident by the fact that he truly was the ugly, divisive character that spawned the nickname “Tricky Dick.”
From Salon • May 14, 2026
Among the most important discoveries was wave-particle duality, the idea that particles can also act like waves.
From Science Daily • Apr. 28, 2026
This is typical Morris: a claim of duality that demands the spotlight while refusing to be knowable.
From The Wall Street Journal • Apr. 23, 2026
One reason why I wanted the Grammy was so that I could continue doing background because it gives me duality.
From Los Angeles Times • Apr. 14, 2026
Using the wave/particle duality discussed in the last chapter, everything in the universe, including light and gravity, can be described in terms of particles.
From "A Brief History of Time: And Other Essays" by Stephen Hawking
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.
