Shitty way of spelling the word "muzak" which is a type of instrumental elevator music from the 70's. Now muzak is commonly refered to as anytype of music.
"I played some muzack with Nick and Colin on Sunday"
The unique muzak (with no words) that was commonly played during episodes of Saved by the Bell. Especially common playing on the juke box at the Max, on the KTTY Bayside radio station, and as the soundtracks to movies that the gang watched.
Kelly got jealous when Zack played the muzack that used to be 'their song' on the juke box at the Max and danced with another girl.