Definition of chin music:
(n) :
(US, slang, dated) Idle talk; chatter.
(n) :
(baseball, informal) A fastball thrown near the batter's chin, often to set up a subsequent pitch thrown low and outside.
(n) :
(cricket, informal) A bouncer aimed near the batsman's chin.
(n) :
(folk music, informal) Rhythmic singing, usually to nonsense syllables, in a style partly inspired by the instruments used to accompany folk dancing in Irish and Scottish traditions.