Critical Information Infrastructure (CII)

Critical Information Infrastructure (CII) constitutes assets (real/virtual), networks, systems, processes, information, and functions that are vital to a nation such that their incapacity or destruction would have a devastating impact on national security, the economic and social well-being of citizens. CII may comprise a number of different infrastructures with essential interdependencies and critical information flows between them.

Source: https://www.cisa.gov/topics/critical-infrastructure-security-and-resilience/critical-infrastructure-sectors