anti-matter

Noun

antimatter (usually uncountable, plural antimatters)

1. (usually) Matter that is composed of the antiparticles of those that constitute normal matter.
   • 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.2023 September 27, Hannah Devlin, “Scientists find antimatter is subject to gravity”, in The Guardian, →ISSN
2. (usually) A form of matter that has a key property, such as charge, opposite to that of ordinary matter.
   • 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.2010 November 19, Alok Jha, “We can't see antimatter but it really does matter”, in The Guardian, →ISSN