in·ter·face

n. in-ter-feys;
v. in-ter-feys, in-ter-feys]

–noun

1. a surface regarded as the common boundary of two bodies, spaces, or phases.
2. the facts, problems, considerations, theories, practices, etc., shared by two or more disciplines, procedures, or fields of study: the interface between chemistry and physics.
3. a common boundary or interconnection between systems, equipment, concepts, or human beings.
4. communication or interaction: Interface between the parent company and its subsidiaries has never been better.
5. a thing or circumstance that enables separate and sometimes incompatible elements to coordinate effectively: The organization serves as an interface between the state government and the public.

–verb (used with object)

1. to bring into an interface.
2. to bring together; connect or mesh: The management is interfacing several departments with an information service from overseas. –verb (used without object)
3. to be in an interface.
4. to function as an interface.
5. to meet or communicate directly; interact, coordinate, synchronize, or harmonize (often fol. by with ): The two communications systems are able to interface with each other.

source: http://dictionary.reference.com/browse/interface