I am little bit confused about the following topics which are related to Oracle Forms

1. Form Designer
2. Form Generator
3. Form Runtime or Run Form

Form Designer: A forms designer provides design-time services and a facility for developers to design forms. The designer host works with the design-time environment to manage designer state, activities (such as transactions), and components. In addition, there are several concepts relating to the components themselves that are important to comprehend. 

Now I am looking for the definition Form Generator & Form Runtime.