Pronunciation: (nOO-trē'nō, nyOO-), [key]
—pl. -nos. Physics.
any of the massless or nearly massless electrically neutral leptons. There is a distinct kind of neutrino associated with each of the massive leptons. Cf. antineutrino, lepton, conservation of lepton number.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.