Interface

In general usage, an interface is the point, area or surface along which two substances or other qualitavely different things meet; it is also used metaphorically for the juncture between items.

1. In a system, a shared boundary, i.e., the boundary between two subsystems or two devices.

2. A shared boundary between two functional units, defined by specific attributes, such as functional characteristics, common physical interconnection characteristics, and signal characteristics.

3. A point of communication between two or more processes, persons, or other physical entities.

4. A point of interconnection between user terminal equipment and commercial communications facilities.

5. To interconnect two or more entities at a common point or shared boundary.

Source: from Federal Standard 1037C and from MIL-STD-188

See also: network interface, network card