antimatter

• anti-matter

From anti- +‎ matter. Coined by British physicist Arthur Schuster in 1898 to describe matter that resists gravity in a jocular article in Nature titled "Potential Matter.—A Holiday Dream", but not used in a modern sense until the 1940s.

• (General American) IPA^(key): /ˈæn.tiˌmæt.ɚ/, /ˈænˌtaɪˌmæt.ɚ/, [ˈæn.tiˌmæ.ɾɚ], [ˈæ.ɾ̃iˌmæ.ɾɚ], [ˈæ.niˌmæ.ɾɚ]

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antimatter (usually uncountable, plural antimatters)

1. (physics) Matter that is composed of the antiparticles of those that constitute normal matter.
   • 2023 September 27, Hannah Devlin, “Scientists find antimatter is subject to gravity”, in The Guardian‎, →ISSN:

     But most theories predict that equal amounts of matter and antimatter should have been produced during the big bang, and the mystery of what happened to all the antimatter is a central question in fundamental physics.

2. (physics) A form of matter that has a key property, such as charge, opposite to that of ordinary matter.
   • 2010 November 19, Alok Jha, “We can't see antimatter but it really does matter”, in The Guardian‎, →ISSN:

     Particles of matter and antimatter are identical, except for an opposite electrical charge. An electron has a negative charge whereas its antiparticle, the positron, has a positive charge, and both have an identical mass.

• antimatter rocket

• antiparticle