Prologue (noun)

1. An introduction to a play, novel, or other literary work, giving background information about the story or setting.
2. A speech or statement made before a performance or event.

Origin:

From old french prologe, from latin prologus, from greek prologos "speaking before", from pro- "before" + logos "speech".

Examples:

1. The prologue of the play provided important context for understanding the characters and their motivations.
2. In the prologue of his novel, the author gave a brief history of the fictional world in which the story takes place.
3. The prologue of the film was a montage of historical footage that set the stage for the story to come.
4. The opera singer gave a prologue before beginning her performance, thanking the audience for coming.
5. The prologue of the conference was a keynote speech by a renowned expert in the field.