API - application program interface; application programming interface

set of routines, protocols, and tools for building software applications
[SOURCE: ISO 17627:2009, 2.4, modified]
NOTE 1 to entry: An API expresses a software component in terms of its operations, inputs, outputs, and underlying types; it defines functionalities that are independent of their respective implementations, which
allows definitions and implementations to vary without compromising the interface. An API can also assist otherwise distinct applications with sharing data, which can help to integrate and enhance the functionalities of
the applications.
NOTE 2 to entry: APIs often come in the form of a library that includes specifications for routines, data structures,
object classes, and variables. In addition to accessing databases or computer hardware, such as hard disk drives or video cards, an API can be used to ease the work of programming graphical user interface components.

Application Area: ITS Spatial data and ITS Database technology, ITS Architecture