I think it is a motive.
A Motive
A group of Musical Instruments is called a consort.
synthesizer
A short musical idea can be called a number of things. It can be called a phrase or motif for example.
tangaia
An "understudy."
Psalm.
It's called an etude - i.e. A musical composition written solely to improve technique.
A numbered musical piece might be called a concerto, an opus, or a composition. It could also be called a symphony.
Study
instrumental
A group of Musical Instruments is called a consort.
Basso continuo
Two singers are a duo.They might sing a duet, a musical composition for two performers.
The movement of rock fragments is called erosion.
Okazaki fragments.
One of two: 1) A Quartet 2) A Piano Trio
They can vary. They can either be called:ConcertoOrIntroduction and allegro