Neutrino

Part of speech: noun

Definitions

1. A nearly massless particle that carries no electric charge and emerges during processes such as nuclear reactions and certain types of decay
2. An elementary particle characterized by its lack of electric charge and minimal mass, significant in nuclear processes and astrophysical phenomena
3. A fundamental particle with extremely low mass and no electrical charge that is produced in nuclear reactions and particle decays

Etymology: Enrico Fermi coined "neutrino" in 1933 while developing his theory of beta decay, and the name is a joke at the expense of the neutron. "Neutron," the uncharged particle James Chadwick had identified in 1932, was already in use, and Fermi gave the new, even lighter and even more elusive particle a diminutive form: "neutrino" is essentially "little neutron" in Italian style, built from "neutr(o)-" plus the Italian diminutive suffix "-ino." The suffix is what gives the word its charm. Italian "-ino" softens and shrinks a noun, as in "bambino" (little child), so Fermi's choice reflected both the particle's tiny mass and its neutral charge, which made it the neutron's smaller companion. The naming also reflected how Fermi thought about the problem: he needed a particle to carry away energy and angular momentum in beta decay, and the name marked it as a close relative of the neutron rather than something entirely new.

Synonyms: subatomic particle