Interdependency / cross-sector dependency

A dependency is a one-directional link between two pieces of infrastructure, where the state of one influences or relies on the state of the other (a hospital depends on the power grid, but not vice versa in the same way). An interdependency is bidirectional: each infrastructure's state influences and relies on the other's (the power grid depends on natural gas delivery for generation, while gas compressor stations depend on electricity to run). These dependency relationships are what make cascading failure possible.