What do you call a violin songs is it piece or movement?

In classical music, a "piece" is a general term that can refer to a complete musical composition or a section or part of a larger composition. A "movement" is a musical section that is part of a larger work, such as a sonata, concerto, or symphony.

When it comes to violin music, a piece can refer to a solo violin composition, a violin concerto (which features the violin as the solo instrument), or a movement within a larger work that includes the violin. For example, the famous "Violin Concerto in E minor" by Niccolò Paganini is a piece that features the violin as the solo instrument, while the "Andante" movement from the "Symphony No. 3" by Ludwig van Beethoven is a movement that includes the violin as part of the orchestra.

So, in summary, the term "piece" can refer to a complete violin composition or a section of a larger work, while a "movement" is a specific section or part of a larger composition that includes the violin.