interconnected system

A configuration of two or more distinct IT systems—spanning organizational, network, or authorization boundaries—that are directly linked for the purpose of sharing data, resources, or services. What distinguishes it from a single system with internal components is the presence of a cross-boundary connection that introduces shared risk: each party's security and privacy posture can affect the other's, which is why authority documents treat the connection itself as a security object requiring its own governance instruments (interconnection security agreements, architectural controls, and joint authorization). In practice, standards bodies use the term to frame obligations such as mandating specific architectural constraints, documenting mutual protection requirements, and maintaining the confidentiality, integrity, and availability of information as it moves across the join.