Musical works are compositions that are written to be performed by musicians. CANONS are a type of musical composition in which two or more voices sing the same melody at different times, often in a round. Opuses are a type of musical composition that is usually numbered and is often part of a larger work. Rondos are a type of musical form that consists of a main theme alternating with different episodes. Sonatas are a type of musical composition that is usually written for a solo instrument. OPERA is a type of musical theatre that combines singing, acting, and dancing. Etudes are a type of musical composition that is used to practice a particular technique. Violin concertos are a type of musical composition that is written for a solo violin and an orchestra.