antiparticle

noun

an·​ti·​par·​ti·​cle ˈan-tē-ˌpär-ti-kəl How to pronounce antiparticle (audio) ˈan-ˌtī- How to pronounce antiparticle (audio)
: a subatomic particle identical to another subatomic particle in mass but opposite to it in electric and magnetic properties (such as sign of charge) that when brought together with its counterpart produces mutual annihilation
especially : a subatomic particle not found in ordinary matter

Examples of antiparticle in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The trap also maintains an ultrahigh vacuum so that there’s no chance that any regular particles will collide with the antiparticles. — Emma Gometz, Scientific American, 25 Mar. 2026 When a particle encounters its antiparticle, the two annihilate each other in a burst of energy. — Alexey A. Petrov, The Conversation, 25 Nov. 2025 When a particle and its antiparticle behave differently, physicists say that charge-parity has been violated. — Discover Magazine, 26 Mar. 2025 As scientists understand the universe today, for every type particle that exists, there is a corresponding antiparticle, exactly matching the particle but with an opposite charge. — ABC News, 23 Mar. 2026 See All Example Sentences for antiparticle

Word History

First Known Use

1934, in the meaning defined above

Time Traveler
The first known use of antiparticle was in 1934

Rhymes for antiparticle

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Browse Nearby Words

antiparasitic
antiparticle
anti-party
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Cite this Entry

“Antiparticle.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/antiparticle. Accessed 10 Jul. 2026.

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Kids Definition

antiparticle

noun
an·​ti·​par·​ti·​cle ˈant-i-ˌpärt-i-kəl How to pronounce antiparticle (audio)
ˈan-ˌtī-
: an elementary particle identical to another elementary particle in mass but opposite to it in electric or magnetic properties

More from Merriam-Webster on antiparticle

Britannica.com: Encyclopedia article about antiparticle

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