a hypothetical or supposed world or universe composed of antimatter
antiworld in American English
(ˈæntiˌwɜːrld, ˈæntai-)
noun
(often anti-worlds) Physics
a hypothetical world composed of antimatter
Word origin
[anti- + world]anti- is a prefix meaning “against,” “opposite of,” “antiparticle of,” used in the formationof compound words (anticline); used freely in combination with elements of any origin (antibody; antifreeze; antiknock; antilepton)