Call

1. In communications, any demand to set up a connection.
2. A unit of traffic measurement.
3. The actions performed by a call originator.
4. The operations required to establish, maintain, and release a connection.
5. To use a connection between two stations.
6. The action of bringing a computer program, a subprogram, or a subroutine into effect, usually by specifying the entry conditions and the entry point[?].

Source: from Federal Standard 1037C and from MIL-STD-188