To learn what an "interface" means in terms of Iguana, see What is an Interface?

An interface in the software industry could mean many different things, with the most common meaning being associated with a graphical user interface (GUI). Of course, "GUI" is the means by which users interact with a software or hardware application.

In terms of Chameleon, the meaning of "interface" becomes quite different. The message definition file (VMD) is referred to as an "interface" because it acts as a bridge between the HL7 world and your application, as shown in the following diagram:

Interface Overview

What's important to note is that the "interface" to your application is created inside the VMD file using tables. These tables are used as data objects that your application will interface with. In turn, data is mapped from incoming messages to these tables (or vice-versa).