A communications circuit that interconnects switches. As such, multiple users and multiple transmissions can share a trunk on a pooled basis, with contention for trunk access managed by an intelligent switching device. There are many types of trunks. Tie trunks connect Private Branch Exchange (PBX) switches in a private network, Central Office Exchange (COE) trunks connect PBXs to telephone company central office exchange switches, and interoffice trunks interconnect central office exchange switches. Trunk groups are groups of trunks serving the same special purpose.Trunks traditionally are directional in nature, with the options being one-way outgoing (originating), one-way incoming (terminating), or twoway (combination).The term trunk comes from the Latin truncus, literally meaning something cut off. Trunk distinguishes the main body of a circuit from the lesser subsidiary lines that come off it, much as the main channel of a river is apart from its lesser tributaries. See also line and trunk group.