An orchestral piece introducing an opera or other longer work, or one written for concert performance. Overtures to mid-17th-century Venetian operas typically consisted of a slow section in duple metre followed by a faster one in triple; this served as a model for the French Overture developed by Lully, Purcell, Handel and others. In Germany, 'Overtüre' was often used for an orchestral suite beginning with an overture of this type. The Italian overture, developed at Naples in the late 17th century, was in three short sections (fast-slow-fast), often with a prominent trumpet part. This type, or rather its first section extended on sonata lines, survived into the Classical period, but it was not until Gluck and Mozart that composers began to connect the overture thematically or in other ways to the opera that followed. The standard operatic overture between 1790 and 1820 consisted of a slow introduction and a fast movement in common time and in sonata form but without repeats and with little or no melodic development.

After Wagner's "Tannhäuser" (1845) independent overtures to serious operas were largely replaced by shorter preludes, but the overture survived in comic operas and operettas and as a concert piece. Many concert overtures, such as Mendelssohn's "The Hebrides", are descriptive pieces; others, like Berlioz's "King Lear" and "The Corsair", are based on literary subjects or, like Brahms' "Academic Festival Overture", celebrate a particular event.

The Concert Overture was a symphonic work in the manner of an overture that was not associated with an opera.  In general, the concert overture did not attempt to tell a story but created a mood that can be associated with a literary theme, a place, or an event.  Many works of this nature adhere closely to the principle of the sonata form.