Question

Define neutrino and antineutrino

Answer 1

A neutral subatomic particle with a mass close to zero and half-integral spin, which rarely reacts with normal matter.

The antineutrino is an elementary subatomic particle with infinitesimal mass (less than 0.3eV..?) and with no electric charge

Answer 2

neutrino is a fermion (an elementary particle with half-integer spin) that interacts only via the weak subatomic force and gravity

The antineutrino (or anti-neutrino) is a lepton, an antimatter particle, the counterpart to the neutrino.