IPA: //ˈbændmeɪt//
KK: /bændmeɪt/
A person who plays music or sings in the same band as someone else.
She has been friends with her bandmate since they started playing together.
Bandmate → It is formed from "band" (from Old English *banda*, meaning a group or a bond) and "mate" (from Old English *gemetta*, meaning companion or friend). The word "bandmate" refers to a companion or member of a musical group or band.
Think of a 'group' ('band') of 'companions' ('mate') making music together — that's what a bandmate is.