The history of the opera overture goes back to the beginning of the 17th century. Instruments were different back then (think gut strings and the violoncello), the symphony hadn’t been invented yet, and opera was just getting started. Thanks to guys like Peri, Caccini, and Monteverdi, operas and overtures were able to get off the ground. The word “overture” comes from the Latin word “apertura.” You may be familiar with the English word “aperture,” which refers to an opening or a hole. Considering the origins of the word, it comes as no surprise that “overture” is used to describe the instrumental opening of an opera before the beginning of Act 1.

Source: Musika Lessons