A musical composition is a creative work of music that is usually written by a composer. An ORATORIO is an extended musical composition for orchestra, choir, and soloists. An opus is a musical composition, often numbered to designate the order of a composer's works. A septet is a composition for seven instruments or voices. An etude is a short musical composition, usually for the practice of a particular technique. A PIECE is a separate section of a musical composition. A toccata is a virtuosic, fast-paced musical composition. A fugue is a contrapuntal composition in which a short melody or phrase is introduced by one part and successively taken up by others. A FANTASIA is a free-form musical composition. A SONG is a short musical composition with words. A sonata is a musical composition of several movements for one or more instruments. A NONET is a composition for nine instruments or voices. A motet is a polyphonic choral composition on a sacred text. An OCTET is a composition for eight instruments or voices. A rondo is a musical form consisting of a theme and variations. A SUITE is a set of musical pieces in the same key. An arioso is a type of lyrical vocal composition. A CONCERTO is a composition for one or more solo instruments and orchestra. A SERENADE is a light, romantic musical composition. A sonatina is a short, simple sonata.