A positively charged meson composed of a charm quark and a bottom antiquark and having a mass about 12,300 times that of an electron and a mean lifetime of about 4.6 × 10-13 second.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.