antiparticle

noun

an·​ti·​par·​ti·​cle

ˈan-tē-ˌpär-ti-kəl,

ˈan-ˌtī- 

: 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

When a particle and its antiparticle behave differently, physicists say that charge-parity has been violated. —Discover Magazine, 26 Mar. 2025

Then, a few months later, an even heavier antiparticle — anti-hyperhelium-4 that is made from two anti-protons, an anti-neutron and an anti-hyperon — was detected by the ALICE (A Large Ion Collider Experiment) instrument at the LHC. —Keith Cooper, Space.com, 25 Dec. 2024

There’s a very real possibility that neutrinos are also their own antiparticles. —Paul Sutter, Ars Technica, 11 June 2024

But through some very complex and exceedingly technical processes, a particle that is its own antiparticle can acquire a mass. —Paul Sutter, Ars Technica, 11 June 2024

Word History

First Known Use

1934, in the meaning defined above

Rhymes for antiparticle

• article
• particle
• interparticle
• nanoparticle
• quasiparticle

Kids Definition

antiparticle

noun

an·​ti·​par·​ti·​cle ˈant-i-ˌpärt-i-kəl 

ˈan-ˌtī-

: an elementary particle identical to another elementary particle in mass but opposite to it in electric or magnetic properties