From Longman Business Dictionary
interfacein·ter·face1 /ˈɪntəfeɪs-ər-/ noun [countableC]1the point at which two subjects, events etc are connected with each other or have an effect on one anotherinterface betweenThe next chapter discusses the interface between accountancy and the law.
2COMPUTING the way that a particular computer program shows information on the screen to the userthe Windows user interface
→ graphical user interface3COMPUTING the part of a computer system that connects two different machines or systemsthe interface between the computer and the printer