It was first used in the 17th century to describe the large-scale musical dramas that were becoming popular in Italy. These works combined music, singing, acting, and elaborate sets and costumes to tell a story.
The term "opera" evolved from the more specific phrase "opera in musica" (work in music), which was used to distinguish these dramatic works from other forms of musical performance.
Over time, "opera" became the standard term for this type of theatrical music, and its meaning has remained consistent throughout history.