antiparticle

noun

1. (particle)A subatomic particle corresponding to another particle with the same mass, spin and mean lifetime but with charge, parity, strangeness and other quantum numbers flipped in sign; a particle that has a reversed world line to another.

   “There could be whole antiworlds and antipeople made out of antiparticles. However, if you meet your antiself, don't shake hands!”

   “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.”