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
Example Sentences
Recent Examples on the Web The first and most well-known parameter, charge-parity (CP) violation, dictates whether neutrinos and their antiparticle counterparts oscillate in the same way, and could help explain why there is more matter than antimatter in the universe. 
Thomas Lewton, Scientific American, 13 Apr. 2022 This leaves behind the second square’s opposite side, also consisting of a particle and an antiparticle. Quanta Magazine, 26 July 2021 This leaves behind the second square’s opposite side, also consisting of a particle and an antiparticle. Quanta Magazine, 26 July 2021 This leaves behind the second square’s opposite side, also consisting of a particle and an antiparticle. Quanta Magazine, 26 July 2021 In the first step of this fusion process, two protons inside the sun fuse into a deuteron while giving off a neutrino and a positron—the antiparticle of the electron. Scientific American, 1 Feb. 2022 The antiparticle version of an electron, for instance, is a positron. Caroline Delbert, Popular Mechanics, 21 Sep. 2021 The resultant movement is that of a particle-antiparticle pair moving sideways in a straight line. Thomas Lewton, Wired, 1 Aug. 2021 This self-annihilation is like that of a particle and antiparticle pair, except that here both members of the pair are identical. Quanta Magazine, 29 Sep. 2021 See More
Thomas Lewton, Scientific American, 13 Apr. 2022 This leaves behind the second square’s opposite side, also consisting of a particle and an antiparticle. Quanta Magazine, 26 July 2021 This leaves behind the second square’s opposite side, also consisting of a particle and an antiparticle. Quanta Magazine, 26 July 2021 This leaves behind the second square’s opposite side, also consisting of a particle and an antiparticle. Quanta Magazine, 26 July 2021 In the first step of this fusion process, two protons inside the sun fuse into a deuteron while giving off a neutrino and a positron—the antiparticle of the electron. Scientific American, 1 Feb. 2022 The antiparticle version of an electron, for instance, is a positron. Caroline Delbert, Popular Mechanics, 21 Sep. 2021 The resultant movement is that of a particle-antiparticle pair moving sideways in a straight line. Thomas Lewton, Wired, 1 Aug. 2021 This self-annihilation is like that of a particle and antiparticle pair, except that here both members of the pair are identical. Quanta Magazine, 29 Sep. 2021 See More Word History
First Known Use
1934, in the meaning defined above