My brother is a violin player in the school orchestra.

violin的意思是"小提琴"，一种四弦的弓弦乐器。 player是名词，来自动词 play（演奏、玩耍），本义是"演奏者"或"玩家"。 violin player指"小提琴演奏者"，即"小提琴手"。