supplies [plural] : things (such as food, equipment, fuel, etc.) that are needed for a particular purpose and that will be used by a particular person or group. 1  They took a month's worth of supplies on the camping trip. 2  The town is in need of basic medical supplies. 3  a store that sells art/office/cleaning supplies.
The last and largest section covers end-user applications and application protocols, including general file transfer, electronic mail, Usenet, the World Wide Web, interactive protocols (such as Telnet) and administration utilities. 1  Name Systems and TCP/IP Name Registration and Name Resolution.
An application programming interface (API) is (as the name suggests) an interface for your application to use code that does not belong to your application (usually a library). Usually, an API is comprised of a set of function/method calls that can be made to the library by your application. All system calls together constitute an API that the operating system (kernel) provides to applications that run on that platform.