The Title property of the Legend allows setting the Legend title. The full path to this property is Legend.Title. If the field of the Title property is not filled then the Legend title is not shown. The Title is shown over the Legend. The picture below shows a sample of the Chart with Legend where the "Title Legend" is the Legend title:
The Title property has the following properties:
TitleColor - sets the Title color;
TitleFont - sets the Title font size and font style.