beta particle
Physics a high-speed electron or positron emitted by a nucleus during radioactive decay or nuclear fission
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
beta particle
An energetic electron or positron ejected by beta decay.Collins Dictionary of Astronomy © Market House Books Ltd, 2006
beta particle
[′bād·ə ‚pard·ə·kəl] (nuclear physics)
An electron or positron emitted from a nucleus during beta decay.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.