Antimatter (Def 1)
Chemistry
Form of matter that is composed of the antiparticles of the corresponding particles in matter
Antimatter (Def 2)
Phy Extra
Matter composed of antiparticles, which have the same mass as particles of ordinary matter but opposite charges
Antimatter (Def 3)
Physics
Matter composed of elementary antiparticles, in which protons are replaced by antiprotons, electrons by positrons, and so on. When such matter and ordinary matter come into contact, they both are annihilated.