an ‧ ti ‧ mat ‧ ter /ˈæntiˌmætə $ -ər/ BrE AmE noun [uncountable]
a form of ↑ matter (30) (=substance which the things in the universe are made of) consisting of antiparticles
an ‧ ti ‧ mat ‧ ter /ˈæntiˌmætə $ -ər/ BrE AmE noun [uncountable]
a form of ↑ matter (30) (=substance which the things in the universe are made of) consisting of antiparticles
Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012