Duet

A duet is a musical composition for two performers, most often used for a vocal or piano duet. For other instruments, the word duo is often used. 

The word duet is used in any of the following ways:
a pair of musicians playing the same musical instrument,
a pair of musicians playing different instruments,
the performance of a song by two people,
a piece of music that can be performed by two people,
as a general term for any activity done by two people.

References

Category:Music