From Academic Kids
A peer group is a group of people of approximately the same age, social status, and interests. Some peer groups are socialized by the streets rather than by their families or conventional institutions. They define themselves as a gang.
In Open Systems Interconnection (OSI) Architecture, a peer group is a group of functional units in a given layer of a network in which all the functions performed by the functional units extend throughout the system at the same layer.de:Peer Group