antimatter

noun

an·​ti·​mat·​ter ˈan-tē-ˌma-tər How to pronounce antimatter (audio) ˈan-ˌtī- How to pronounce antimatter (audio)
: matter composed of antiparticles

Examples of antimatter in a Sentence

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The composition of these jets isn’t crystal clear, but scientists suspect electrons, positrons (the antimatter versions of electrons) and perhaps protons are pulled along swirling magnetic lines before being sent out from the black hole’s poles. — Robin George Andrews, Scientific American, 20 Oct. 2026 For example, neutrinos may give researchers their best shot at learning why the universe is predominantly made of matter, rather than equal parts matter and antimatter. — Doug Cowen, The Conversation, 8 Oct. 2026 What happens when the invisible string connecting two fundamental particles—a quark and its antimatter counterpart, an antiquark—is stretched so far that new particles can begin to form? — Rupendra Brahambhatt, Interesting Engineering, 27 Sep. 2026 The main way that happens is by colliding electrons and their antimatter partners, positrons. — Matt Von Hippel, Quanta Magazine, 29 July 2026 See All Example Sentences for antimatter

Word History

First Known Use

1934, in the meaning defined above

Time Traveler
The first known use of antimatter was in 1934

Rhymes for antimatter

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Browse Nearby Words

anti-materialism
antimatter
antimechanized
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Cite this Entry

“Antimatter.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/antimatter. Accessed 27 Oct. 2026.

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Kids Definition

antimatter

noun
an·​ti·​mat·​ter ˈant-i-ˌmat-ər How to pronounce antimatter (audio)
: matter whose parts match parts of ordinary matter except in having some opposite properties (as a positive instead of a negative charge)

More from Merriam-Webster on antimatter

Britannica.com: Encyclopedia article about antimatter

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