The drumset is mainly an ensemble instrument. It and the bass keep time, though there are exceptions...
As an ensemble or solo instrument ...
solo
It can be performed by a solo instrument, such as a piano or violin, or by a small group like a string quartet or chamber ensemble.
A solo is one person playing/singing ect. An ensemble is a group of many persons playing/singing together.
It is an ensemble piece with solo instruments featured, the piece cannot achieve its purpose being played as a solo.
The solo instrument is a violin.
An instrument solo in a band is when every one else is quiet but the one instrument that has the solo.
A flute can be played solo or as part of an ensemble. When played solo, the flutist typically performs alone without accompaniment. Solo flute repertoire includes pieces specifically written for the instrument, such as concertos and sonatas, as well as arrangements of music originally composed for other instruments or ensembles. The flute's versatile range and expressive capabilities make it well-suited for solo performance in various musical genres.
A work for orchestra and solo instrument is called a concerto.
That depends, although sonata's are always for one or a very small group of instruments. Most commonly, piano solo, violin and piano, cello and piano, flute and piano, a wind instrument, a string instrument and a piano... It varies.. But its always a small ensemble.
A concerto is a work in three movements, rather than the four movements of a symphony, in which a solo instrument or ensemble is accompanied by an orchestra. The concerto developed earlier than the symphony. As in the symphony, the first movement of the classical concerto is generally in sonata-allegro form, followed by a slow movement and a finale usually in rondo form. The concerto had arisen in the Baroque period, in two types. One was the concerto grosso, in which a small ensemble within the orchestra is contrasted to and accompanied by the full complement. The other was the solo concerto as described.
A concerto is a work in three movements, rather than the four movements of a symphony, in which a solo instrument or ensemble is accompanied by an orchestra. The concerto developed earlier than the symphony. As in the symphony, the first movement of the classical concerto is generally in sonata-allegro form, followed by a slow movement and a finale usually in rondo form. The concerto had arisen in the Baroque period, in two types. One was the concerto grosso, in which a small ensemble within the orchestra is contrasted to and accompanied by the full complement. The other was the solo concerto as described.