From Longman Dictionary of Contemporary Englishmusomu‧so /ˈmjuːzəʊ $ -zoʊ/ noun (plural musos) [countable] British English informal someone who plays popular music or knows a lot about it
Examples from the Corpus
muso• Come blues, of course, find expression through raw urban rock juices rather than standard muso stodge.• Perhaps the reason Zeppelin were so despised after the punk revolution was the fact that they were the ultimate muso band.Origin muso (1900-2000) musician 