Keynote

Talk that establishes an underlying theme

A keynote in public speaking is a talk that establishes a main underlying theme. In corporate or commercial settings, greater importance is attached to the delivery of a keynote speech or keynote address. The keynote establishes the framework for the following programme of events or convention agenda; frequently the role of keynote speaker will include that of convention moderator. It will also flag up a larger idea—a literary story, an individual musical piece, or event.

This keyword could refer to multiple things. Here are some suggestions: