from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An electrically neutral subatomic particle in the baryon family, having a mass 1,839 times that of the electron, stable when bound in an atomic nucleus, and having a mean lifetime of approximately 1.0 × 103 seconds as a free particle. It and the proton form nearly the entire mass of atomic nuclei. See Table at subatomic particle.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A subatomic particle forming part of the nucleus of an atom and having no charge; it is a combination of an up quark and two down quarks
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. an elementary particle with 0 charge and mass about equal to a proton; enters into the structure of the atomic nucleus
neutr(al) + -on1.(American Heritage® Dictionary of the English Language, Fourth Edition)