antiparticle

1. (particle physics) 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.Examples: "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."particle