Concerto \Con*cer"to\ (?; It. ?), n.; pl. Concertos. [It. See Concert, n.]

(Mus.) A composition (usually in symphonic form with three movements) in which one instrument (or two or three) stands out in bold relief against the orchestra, or accompaniment, so as to display its qualities or the performer's skill.

Source: Webster's Revised Unabridged Dictionary (1913)