n. (Abbr. 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.
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
