During the concert intermission, the singer performed a three-song mini-set.

mini-set 是由前缀 mini-（表示"小的、微型的"）和名词 set（"一套、一组"）组成的复合名词。mini-set 指"小型表演组合"，在这里特指"由三首歌组成的短小表演环节"。