A part is the line or lines of music read by an individual performer or multiple performers of the same instrument. For example, the viola section of an orchestra consists of a group of violists reading the same music, known as the viola part.

 

A part may also be a single melodic strand of a polyphonic or contrapuntal texture, as in two-part counterpoint and four-part harmony. In this context, "voice" can also be used to mean "part."

 

Finally, a part may be a section of a larger composition, used primarily to describe a musical form, for example three-part song form.