antiparticle (plural antiparticles)
- (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
a subatomic particle
- The symbol for an antiparticle is the symbol for the normal particle plus "bar" (e.g. pbar) or with a bar above the symbol.