mu|on|i|um

mu|on|i|um «myoo ON ee uhm», noun.

a short-lived particle consisting of a positively charged mu-meson bound to a single electron: »

The positive muon has been observed to collect a negative electron when coming to rest in pure gases, and the resulting “atom,” muonium, has been studied with great precision (Leon M. Lederman).

╂[< muon + -ium, as in uranium]