point of contact or Dividing line
The word interface has an interesting, double meaning. It can mean both ‘point of contact’ and ‘dividing line’.
In as far as the term is used in E-learning, ‘interface’ is more or less the 'organization of visual and functional elements on a display screen'. The visual elements determine the look (or design) of a program; and the interactive style determines the feel of the programme.
The interface should 'connect' the user with the content of the program. A proper interface does just this and therefore forms a point of contact. An unsuitable interface doesn't, and forms a dividing line.
Our web designers are fully aware of this and are always looking for points of contact.