The term for a composition written for a solo instrument, typically showcasing the performer's skill and technique, is "solo piece" or "solo composition." However, there is a more specific term that is commonly used for this type of composition: "solo concerto." A solo concerto is a musical composition that features a solo instrument accompanied by an orchestra or ensemble. It is designed to highlight the virtuosity and expressive capabilities of the soloist while providing a contrast between the solo instrument and the accompanying ensemble. The soloist takes center stage and performs intricate passages, expressive melodies, and technical feats, demonstrating their mastery of the instrument. Some famous examples of solo concertos include Beethoven's Piano Concerto No. 5 "Emperor," Mozart's Clarinet Concerto, and Tchaikovsky's Violin Concerto.