An instrument is any device designed to produce musical sound. The category includes objects as simple as a pair of sticks and as complex as a pipe organ or a modular synthesizer. Classification systems group instruments by how they generate sound: strings, winds, brass, percussion, or electronic means.

Each instrument has its own technique, repertoire, and expressive possibilities. Learning an instrument develops physical coordination, aural skills, and an understanding of musical structure. Some instruments are primarily melodic; others primarily harmonic or rhythmic; many can serve multiple roles.

Technological change continually expands the range of available instruments. Electric amplification, digital synthesis, and computer control have added new families alongside the acoustic instruments that have existed for centuries. The choice of instrument shapes both the music that can be made and the social contexts in which it is performed.

Ultimately every instrument is a tool for turning human intention into organized sound.