A relationship between two network devices, e.g. routers, which are connected by one media segment so that a packet sent by one can reach the other without going through another network device.The concept of adjacency is important in the exchange of routing information.Adjacent SNAnodes are nodes connected to a given node with no intervening nodes.In DECnet and OSI, adjacent nodes share a common segment (Ethernet, FDDI, {Token Ring}).(1998-03-10)