A positively charged meson composed of a charm quark and a strange antiquark and having a mass 3,852 times that of an electron and a mean lifetime of about 5.0 × 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.