What is a solo with accompaniment called?

A solo with accompaniment is called a concerto. A concerto is a musical composition for a solo instrument or instruments, accompanied by an orchestra. The soloist is typically a virtuoso performer, and the concerto allows them to showcase their technical skills and musical interpretation. Concertos are often written in three movements, with the first movement typically being in sonata form. The second movement is often a slow movement, and the third movement is often a lively dance or rondo. Concertos have been written for a wide variety of instruments, including the piano, violin, cello, and flute. Some of the most famous concertos include Mozart's Piano Concerto No. 21, Beethoven's Violin Concerto, and Tchaikovsky's Piano Concerto No. 1.