n.
Pronunciation: ' myü- ˌ än
Function: noun
Etymology: contraction of earlier mu-meson, from mu
Date: 1952
: an unstable lepton that is common in the cosmic radiation near the earth's surface, has a mass about 207 times the mass of the electron, and exists in negative and positive forms
– mu · on · ic \ myü- ' ä-nik \ adjective