trunk

In a communications network, a single transmission channel between two points that are switching centers or nodes, or both. 2. [A] circuit between switchboards or other switching equipment, as distinguished from circuits which extend between central office switching equipment and information origination/termination equipment. [47 CFR Pt.36-A] Note: Trunks may be used to interconnect switches, such as major, minor, public and private switches, to form networks.