overture
The opening music played before an opera or musical.
An overture is the orchestral music played at the beginning of an opera, musical, or ballet. The overture sets the mood and often introduces melodies you'll hear later in the performance. When the lights dim and the overture begins, the audience quiets down and prepares for the story about to unfold. Famous overtures like Rossini's “William Tell Overture” or Bernstein's “Candide Overture” are so exciting that orchestras perform them as standalone pieces in concerts.
The word also means an approach or proposal, especially a first attempt to start a relationship or negotiation. When a student makes friendly overtures to a new classmate, they're reaching out to begin a friendship by sitting together at lunch or offering to be partners on a project. Countries make peace overtures when they propose talks to end a conflict. These overtures might be accepted or rejected, but they represent that crucial first step toward something new.
Both meanings share the idea of a beginning: musical overtures begin performances, and diplomatic or social overtures begin relationships.