乐器，泛指可以发声演奏音乐的工具。根据构造或发声原理，乐器可以细分作以下的分类：

• 气鸣乐器(管乐器)
• 弦鸣乐器
• 膜鸣乐器(打击乐器)
• 体鸣乐器(自鸣乐器)

A musical instrument is an instrument created or adapted to make musical sounds. In principle, any object that produces sound can be a musical instrument—it is through purpose that the object becomes a musical instrument. The history of musical instruments dates to the beginnings of human culture. Early musical instruments may have been used for ritual, such as a trumpet to signal success on the hunt, or a drum in a religious ceremony. Cultures eventually developed composition and performance of melodies for entertainment. Musical instruments evolved in step with changing applications.