These are the parts of a program, as shown in the unit Help screen:

The unit heading specifies the unit's name, which is used when referring to the unit in a uses clause.

The interface part declares the symbols that are public (available to the users of the unit). Procedures and functions are listed only as headings in the interface part.

The implementation part defines the "body" of all public procedures and functions. In addition, it declares private symbols that aren't available to the users of the unit.

The initialization part is the last part of a unit. It consists of either