Wordnet 3.0
NOUN (1)
1.
exceedingly short-lived meson;
The Collaborative International Dictionary of English v.0.48:
b-meson \b-meson\ n.
1. an exceedingly short-lived meson.
[WordNet 1.5]
WordNet (r) 3.0 (2006):
b-meson
n 1: exceedingly short-lived meson