in·ter·face 
(ĭntər-fās′)
(ĭntər-fās′)n.
1. A surface forming a common boundary between adjacent regions, bodies, substances, or phases.
2. A point at which independent systems or diverse groups interact: "the interface between crime and politics where much of our reality is to be found" (Jack Kroll).
3. Computers
a. A system of interaction or communication between a computer and another entity such as a printer, another computer, a network, or a human user.
b. A device, such as a cable, network card, monitor, or keyboard, that enables interaction or communication between a computer and another entity.
c. The layout or design of the interactive elements of a computer program, an online service, or an electronic device.
v. (ĭn′tər-fās) in·ter·faced, in·ter·fac·ing, in·ter·fac·es
v.tr.
1. To join by means of an interface.
2. To serve as an interface for.
v.intr.
1. To serve as an interface or become interfaced.
2. Usage Problem To interact or coordinate smoothly: "Theatergoers were lured out of their seats and interfaced with the scenery" (New York Times).
in′ter·facial adj.
Usage Note: The noun interface, meaning "a surface forming a common boundary, as between bodies or regions," has been around since the 1880s. But the word did not really take off until the 1960s, when it began to be used in the computer industry to designate the point of interaction between a computer and another system, such as a printer. The word was applied to other interactions as well—between departments in an organization, for example, or between fields of study. Shortly thereafter, interface developed a use as a verb, but many people objected to it, considering it an example of bureaucratic jargon. The Usage Panel has been unable to muster much enthusiasm for the verb. In our 2011 survey, 57 percent found it unacceptable in an example designating interaction between people: The managing editor must interface with a variety of freelance editors and proofreaders. This level of disapproval is only slightly lower than the 63 percent recorded in our 1995 survey, suggesting that writers who wish to avoid a jargony tone would do well to avoid the usage. In 2011, a slightly larger percentage disapproved of interface in examples indicating interaction between a corporation and the public (66 percent) or between various communities in a city (65 percent).