A neutrino, denoted by the Greek letter ν, is an elementary particle that interacts via weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is so tiny (-ino) that it was long thought to be zero. The rest mass of the neutrino is much smaller than that of the other known elementary particles. The weak force has a very short range, the gravitational interaction is extremely weak due to the minimal mass of the neutrino, and neutrinos do not participate in the electromagnetic or strong interaction.
However, despite their elusive nature, neutrinos play a significant role in the field of particle physics. Their ability to pass through ordinary matter unimpeded and undetected is a key aspect of their study and understanding.