a. an elaborate instrumental composition in three or more movements, similar in form to a sonata but written for an orchestra and usually of far grander proportions and more varied elements. b. an instrumental passage occurring in a vocal composition, or between vocal movements in a composition. c. an instrumental piece, often in several movements, forming the overture to an Opera or the like. d. a concert performed by a symphony orchestra. e. anything characterized by a harmonious combination of elements
A musical symphony is an extended piece in three or more movements for performance by a symphony orchestra.