musical instrument，
“musical”在词组中是作为形容词，表达“音乐的”，“instrument”则是“仪器；工具；乐器；手段；器械”的意思，两者结合就是“乐器”的意思：
A musical instrument is an object such as a piano, guitar, or violin which you play in order to produce music. 乐器是指一件物品，如钢琴、吉他、小提琴这些可以用来产生音乐的物品。
例：
The drum is one of the oldest musical instruments.
鼓是最古老的乐器之一。
Make sure you take time for reading or learning to play a musical instrument orjust hanging out with friends and family.
一定要留出读书或学习演奏一种乐器的时间，或者腾出时间与朋友和家人一起休闲游乐。